Circular RNAs (circRNAs) represent a class of non-coding RNAs that form covalently closed RNA circles with extensive expression and conservation in mammals. Circular RNAs regulate gene expression through acting as competitive endogenous RNAs (ceRNAs) and modulating gene transcription. Accumulating evidence supports the implication of circRNAs in a variety of human diseases, but studies of circRNA role in systemic lupus erythematosus (SLE) are lacking. The present study measured the circRNA expression profiles in T cells from patients with SLE and healthy controls with human circRNA microarray and identified 127 differentially expressed circRNAs in SLE patients. Down-regulation of hsa_circ_0045272 in SLE T cells was verified with quantitative PCR. Jurkat cells with stable hsa_circ_0045272 knockdown were generated using specific lentiviral short hairpin RNA for functional studies. Flow cytometric analysis indicated that hsa_circ_0045272 knockdown significantly up-regulated the early apoptosis of Jurkat cells. Meanwhile, ELISA showed that hsa_circ_0045272 knockdown significantly enhanced interleukin-2 production of activated Jurkat cells. Then, ceRNAs were predicted for hsa_circ_0045272 and the significant down-regulation of two mRNAs predicted as ceRNAs, NM_003466 (PAX8) and NM_015177 (DTX4), but not their corresponding proteins, was validated. Furthermore, dual luciferase reporter assay indicated binding of hsa_circ_0045272 with hsa-miR-6127. Circular RNA-mRNA co-expression networks showed the correlation of circRNAs with mRNAs and provided additional clues to circRNA functions. Our study demonstrated dysregulated circRNAs in SLE and revealed the function of hsa_circ_0045272 in negatively regulating apoptosis and interleukin-2 secretion and its potential mechanism. The implication of hsa_circ_0045272 and other abnormal circRNAs in SLE merits further investigation.

The transcription factor Hex is expressed in the thyroid follicular cells (TFC) and in several other cell types. In TFC, Hex contributes to the control of the tissue-specific gene expression. By means of RT-PCR assays we found a correlation between the Hex and Pax8 (a different tissue-specific transcription factor, expressed in TFC) mRNA levels in normal and neoplastic thyroid tissues. This finding suggested the presence of a functional correlation between the two transcription factors. Therefore, we tested whether Pax8 regulates the transcriptional activity of Hex promoter. Indeed, by using cotransfection experiments in non-thyroidal cells, we show that increasing doses of Pax8 expression vector elicited a dose-dependent increase of the transcriptional activity of Hex promoter. Accordingly, gel-retardation assays indicated that in the Hex promoter are present several Pax8 binding sites. The Pax8 activating effect on Hex promoter was further increased by the contemporary presence of Hex protein. In fact, cotransfection of both Hex and Pax8 expression vectors doubled the transcriptional activity of Hex promoter with respect to the condition in which the Pax8 expression vector only was transfected. In addition, we show that also the transcriptional cofactor APE/Ref-1 cooperated with Pax8 for upregulation of Hex promoter activity. These findings, together with other published data, suggest that a network of functional interactions between transcriptional regulators is present in TFC.

BACKGROUND

Endothelin, via endothelin A receptors (ETA), exerts multiple pathologic effects that contribute to disease pathogenesis throughout the body. ETA antagonists ameliorate many experimental diseases and have been extensively utilized in clinical trials. The utility of ETA blockers has been greatly limited, however, by fluid retention, sometimes leading to heart failure or death. To begin to examine this issue, the effect of genetic disruption of ETA in the nephron on blood pressure and salt handling was determined.

METHODS

Mice were generated with doxycycline-inducible nephron-specific ETA deletion using Pax8-rtTA and LC-1 transgenes on the background of homozygous loxP-flanked ETA alleles. Arterial pressure, Na metabolism and measures of body fluid volume status (hematocrit and impedance plethysmography) were assessed.

RESULTS

Absence of nephron ETA did not alter arterial pressure whether mice were ingesting a normal or high Na diet. Nephron ETA disruption did not detectably affect 24 hr Na excretion or urine volume regardless of Na intake. However, mice with nephron ETA knockout that were fed a high Na diet had mild fluid retention as evidenced by an increase in body weight and a fall in hematocrit.

CONCLUSIONS

Genetic deletion of nephron ETA causes very modest fluid retention that does not alter arterial pressure. Nephron ETA, under normal conditions, likely do not play a major role in regulation of Na excretion or systemic hemodynamics.

Thyroid hormone is essential for normal skeletal development. Hypothyroidism is associated with growth arrest, failure of chondrocyte differentiation, and abnormal matrix synthesis. Thyroid hormone modulates the Indian hedgehog/PTHrP feedback loop and regulates fibroblast growth factor (FGF)/FGF receptor signaling. Because heparan sulfate (HS) proteoglycans (Prgs) (HSPGs) are absolutely required by these signaling pathways, we have investigated whether thyroid status affects HSPG expression within the growth plate. Tibial growth plate sections were obtained from 12-wk-old rats rendered euthyroid, thyrotoxic, or hypothyroid at 6 wk of age, 14-d-old congenitally hypothyroid Pax8-null mice, and TRalpha/TRbeta double-null mice lacking all thyroid hormone receptors. HS and chondroitin sulfate Prg expression was determined by immunohistochemistry using three monoclonal antibodies. There was increased HS staining in growth plates from hypothyroid animals predominantly within the extracellular matrix of reserve and proliferative zones. Cellular HS staining was also increased particularly in prehypertrophic chondrocytes. T3 regulation of HSPG core protein and HS synthetic and modification enzyme expression was studied in ATDC5 cells using semiquantitative RT-PCR. Thyroid hormone negatively regulated expression of the core protein Gpc6, the polymerase Ext1, and the modification enzyme Hs6st2. These studies demonstrate that the expression and distribution of growth plate Prgs are regulated by thyroid hormone, and the regulation of HSPG expression provides an important additional link between FGF and Indian hedgehog signaling and T3. These novel observations suggest that the cartilage matrix and especially HSPGs are critical mediators of the skeletal response to thyroid hormone.

Oncocytic cell tumors (OCTs) of the thyroid include oncocytic cell adenomas (OCAs) and oncocytic cell carcinomas (OCCs). Oncocytic variant of papillary carcinoma (OVPC) has also been described. These tumors may present similar diagnostic problems as their non-oncocytic counterparts, in both conventional histology and fine-needle aspiration biopsies. Several markers were shown able to distinguish benign from malignant thyroid follicular tumors, galectin-3 and HBME-1 being the most promising ones. Controversial data have been reported on their discriminatory potential in the small series of OCTs so far analyzed. We aimed to assess the role of galectin-3 and HBME-1 in a large series of 152 OCTs (including 50 OCAs, 70 OCCs and 32 OVPCs). The expression of PPARgamma protein was also evaluated. Using a biotin-free detection system, the sensitivity of galectin-3 was 95.1%, while that for HBME-1 was nearly 53%. The combination of galectin-3 and HBME-1 increased the sensitivity up to 99%. However, for both markers, the specificity was 88%, lower than that reported for non-oncocytic follicular tumors. PPARgamma protein overexpression was absent in all OCAs tested and present in only 10% of OCCs, confirming previous reports on the low prevalence of PAX8-PPARgamma translocations in OCT and ruling out its role as a potential diagnostic marker of malignancy.

Fallopian tube carcinoma (FTCA) is a very rare cancer type, but may be a useful platform for investigating high grade serous tumors of the pelvis that originate from a serous tubal intraepithelial carcinoma (STIC) precursor. Metastatic tumors from a patient diagnosed with Stage IIIC high grade serous FTCA (P0) were transplanted via intraperitoneal (IP) injection into a small cohort of mice (passage, P1). Patient information was obtained from the medical record. Tumors were grown, harvested and re-implanted or archived through P3. The P3 cohort was treated with saline (n=8) or cisplatin, 5 mg/kg (n=8), weekly for 4 weeks. After sacrifice, tumors from each passage and treatment group were passaged further, frozen or paraffin embedded. The patient underwent optimal cytoreductive surgery for Stage IIIC high grade serous FTCA in the presence of a STIC. The FTCA, areas of STIC and normal appearing FT stained positive for p53, PAX8, pH2AX and mib-1. The patient remained in remission 9 months after platinum-based chemotherapy. IP tumor propagation was readily achieved up to P3 in the mice. Similar to the patient, orthotopic tumors were identified along peritoneal and mesenteric surfaces. Tumor histopathological and molecular features were confirmed and maintained through P3. The P3 cisplatin-treated mice had fewer tumor implants, higher levels of pH2AX and lower levels of mib-1 expression compared to controls. This orthotopic model of platinum sensitive high grade serous FTCA is a viable platform to study the biology and treatment of FTCA and other STIC-related pelvic serous carcinomas.

OBJECTIVE

To analyse the coding region of PAX8 in individuals with congenital (CH) or post neonatal hypothyroidism due to dysgenetic (TD) or eutopic thyroid glands.

METHODS

Forty-three children with CH and TD (13 agenesis, 23 ectopia, and seven hypoplasia), one subject with post neonatal onset of hypothyroidism and thyroid ectopia, 15 children with CH and eutopic thyroid glands and six euthyroid adults with thyroid hemiagenesis were enrolled as cases, along with 120 healthy individuals as controls.

METHODS

Exons 2-8 of the PAX8 were directly sequenced. HeLa and HEK293 cells were transfected with PAX8 wild-type (PAX8-WT), mutant PAX8, p300, thyroid transcription factor 1 (TTF-1) and thyroglobulin promoter pGL3 (TG prom-pGL3). Synergism of TTF-1 with PAX8-WT vs. mutant and activity of PAX8-WT vs. mutant in accompaniment with p300 on TG prom-pGL3 were also assessed. The luminescence produced by PAX8-WT and mutant PAX8 was measured.

RESULTS

Among patients and controls only a 15-year-old girl with thyroid ectopia showed a heterozygous transition of cytosine to thymine at position 674 in exon 6, which changed a conserved threonine at position 225 to methionine (PAX8-T225M). Her father and sister harboured PAX8-T225M without abnormal thyroid phenotypes. PAX8-T225M and PAX8-WT similarly increased luciferase activity and had a similar synergistic effect with TTF-1. At 500 ng p300, however, PAX8-T225M could not significantly increase TG promoter activity when compared to PAX8-T225M alone, while PAX8-WT +500 ng p300 induction was significantly higher than PAX8-WT alone (P < 0.001). Cotransfection of TTF-1 together with PAX8-T225M resulted in rescuing of the lack of synergism with p300.

CONCLUSIONS

PAX8 mutations in congenital hypothyroidism due to dysgenetic or orthotopic thyroid glands are rare. PAX8-T225M is probably a rare variant.

The phenomenon that supraphysiological doses of iodide (I(-)) temporarily inhibit thyroid hormone synthesis is known as thyroid iodide autoregulation. Recovery of thyroid function has been attributed to sodium-iodide symporter (NIS) inhibition, but the diversity of available data makes it difficult to reach definitive conclusions. Iodide excess induces reactive oxygen species production and cell toxicity. However, the roles of the oxidative state of the cell and antioxidant selenoproteins in I(-) autoregulation have never been explored. Here we analyze the effects of high I(-) doses in rat thyroids and in PCCl3 cells in the period comprising I(-) autoregulation (i.e. 0-72 h after I(-) administration), focusing on NIS expression, redox state, and the expression and activity of selenoproteins. Our results show that NIS mRNA inhibition by I(-) does not occur at the transcriptional level, because neither NIS promoter activity nor Pax8 expression or its binding to DNA was modulated. Because I(-) uptake was inhibited much earlier than NIS protein, and no effect was observed on its subcellular localization, we suggest that I(-) is inhibiting NIS in the plasma membrane. The increased reactive oxygen species production leads to an increase in thioredoxin reductase mRNA levels and enzyme activity, which reduces the oxidative stress. Inhibition of thioredoxin reductase at either gene expression or activity levels prevented NIS recovery, thus illustrating a new role played by this selenoprotein in the regulation of cell homeostasis and consequently in I(-) autoregulation.

BACKGROUND

PAX8/PPARγ rearrangement is a common genetic alteration in follicular thyroid carcinoma (FTC) and has been reported with variable frequency in papillary thyroid carcinoma (PTC). The diagnostic and phenotypic features of thyroid nodules positive for PAX8/PPARγ on preoperative examination are not well understood.

METHODS

The prevalence of PAX8/PPARγ rearrangement was analyzed in a series of 2015 consecutive thyroid nodules that underwent molecular analysis on cytology specimens and in 446 surgically removed PTCs. For all PAX8/PPARγ positive cases, cytology and surgical pathology slides were examined and the available clinical records were reviewed.

RESULTS

Twenty-two PAX8/PPARγ rearrangements were identified, including 16 detected preoperatively and 6 postoperatively. The incidence of PAX8/PPARγ in PTC was 1.1%. Cytologically, most of these nodules were diagnosed as a follicular neoplasm (73%), followed by the diagnosis of atypia of undetermined significance (19%), and none of the cases was diagnosed as cytologically malignant. All nodules with PAX8/PPARγ detected preoperatively and surgical follow-up available were found to be malignant, among which the most common diagnosis was the encapsulated follicular variant of PTC. Overall, among 20 PAX8/PPARγ-positive tumors that were surgically excised, 17 (85%) were PTC and 3 (15%) were FTC. On follow-up available for 17 patients (mean, 22.4 months), 16 PAX8/PPARγ-positive cancers showed no evidence of biochemical or structural recurrence, whereas 1 patient with FTC developed bone metastasis.

CONCLUSIONS

In this series, PAX8/PPARγ rearrangement found in thyroid nodules had a 100% predictive value for differentiated thyroid cancer, and was more predictive of PTC than FTC. However, almost all PTC carrying PAX8/PPARγ were encapsulated follicular-pattern tumors, distinguished from FTC only by nuclear features. Although most tumors carrying this mutation appear to be clinically indolent, at least on short-term follow-up, distant metastasis can develop from FTC positive for PAX8/PPARγ.

Hemangioblastoma is a rare tumor of uncertain histotype that typically arises in the cerebellum, quite often in the setting of Von Hippel-Lindau syndrome (VHL). Exceptional cases of hemangioblastoma arising outside the central nervous system have been reported, but little is known about their clinicopathologic and immunohistochemical features. Twenty-two cases of hemangioblastoma arising at peripheral sites were identified in consultation files. Clinical, morphologic, and immunohistochemical features were evaluated. Outcome data were obtained from referring pathologists. Twelve patients were female and 10 male; the median age was 58 years (range, 27 to 79 y). All the tumors were solitary (except 1) and arose in spinal nerve roots (12), kidney (3), intestine (2), orbit (1), forearm (1), peritoneum (1), periadrenal soft tissue (1), and flank (1). Five patients had VHL; another 5 had lesions suggestive of VHL. One patient had tuberous sclerosis. The median tumor size was 4 cm (range, 1.3 to 15 cm). Most tumors were well circumscribed; 6 were poorly marginated-3 eroded the adjacent bone and 1 extended into the pleura. All tumors were composed of an admixed population of plump spindle cells and microvacuolated cells with palely eosinophilic or clear cytoplasm, which often mimicked lipoblasts or renal cell carcinoma. In 5 cases the microvacuolated cells were scant. Spindle cell nuclei were hyperchromatic or vesicular with inconspicuous nucleoli. Four tumors showed marked nuclear pleomorphism. Mitotic activity was low (range, 0 to 2/10 HPF). All tumors had a complex capillary network, with admixed larger thin-walled or thick-walled vessels in a solid and often lobular growth pattern, similar to central nervous system hemangioblastoma. In 9 cases the larger vessels showed a branching hemangiopericytoma-like pattern. No necrosis or lymphovascular invasion was identified. Tumor cells expressed inhibin in 95% (20/21), neuron-specific enolase in 79% (15/19), and S100 protein in 65% (13/20); they also expressed GLUT1 (7/10, mostly weak), SMA (4/5), epithelial membrane antigen (2/8, focal), PAX8 (1/10), and desmin (1/4). Brachyury was consistently negative (0/19), as were keratin, HMB-45, melan-A, and GFAP. CD31 and CD34 highlighted tumor vasculature. Follow-up information was available for 17 patients (range, 5 to 117 mo; median 36 mo). Three patients had locally persistent disease after incomplete resection. True local recurrence or distant metastasis has not been identified in any patient so far. One patient died of metastatic renal cell carcinoma. Peripheral hemangioblastoma is rare, often associated with VHL syndrome, and may mimic some malignant tumors. The immunohistochemical profile can aid diagnosis. Unresectable cases may be locally aggressive, but complete excision appears to be curative. Recognition of this tumor may identify patients in whom testing for VHL syndrome is warranted.

OBJECTIVE

The molecular events that lead to human thyroid cell speciation remain incompletely characterized. It has been shown that overexpression of the regulatory transcription factors Pax8 and Nkx2-1 (ttf-1) directs murine embryonic stem (mES) cells to differentiate into thyroid follicular cells by initiating a transcriptional regulatory network. Such cells subsequently organized into three-dimensional follicular structures in the presence of extracellular matrix. In the current study, human embryonic stem (hES) cells were studied with the aim of recapitulating this scenario and producing functional human thyroid cell lines.

METHODS

Reporter gene tagged pEZ-lentiviral vectors were used to express human PAX8-eGFP and NKX2-1-mCherry in the H9 hES cell line followed by differentiation into thyroid cells directed by Activin A and thyrotropin (TSH).

RESULTS

Both transcription factors were expressed efficiently in hES cells expressing either PAX8, NKX2-1, or in combination in the hES cells, which had low endogenous expression of these transcription factors. Further differentiation of the double transfected cells showed the expression of thyroid-specific genes, including thyroglobulin (TG), thyroid peroxidase (TPO), the sodium/iodide symporter (NIS), and the TSH receptor (TSHR) as assessed by reverse transcription polymerase chain reaction and immunostaining. Most notably, the Activin/TSH-induced differentiation approach resulted in thyroid follicle formation and abundant TG protein expression within the follicular lumens. On stimulation with TSH, these hES-derived follicles were also capable of dose-dependent cAMP generation and radioiodine uptake, indicating functional thyroid epithelial cells.

CONCLUSIONS

The induced expression of PAX8 and NKX2-1 in hES cells was followed by differentiation into thyroid epithelial cells and their commitment to form functional three-dimensional neo-follicular structures. The data provide proof of principal that hES cells can be committed to thyroid cell speciation under appropriate conditions.

PAX8 and WT1 are transcription factors, each of them with distinct roles in organogenesis, morphogenesis, cell growth, and differentiation. Recently, their expression was also confirmed in a variety of malignancies, being included in the antibodies panel recommended for the female genital tract pathology. The aim of our study was to evaluate PAX8 and WT1 in different types of ovarian cancer (OC) with focus on (i) the completion of evidences of the Müllerian origin and (ii) the establishment of primary ovarian tumor status vs. metastasis. The study group consisted of 86 cases, with histopathological diagnosis covering the main subtypes of OC (low- and high-grade serous, low- and high-grade endometrioid, clear cell, mucinous, malignant Brenner tumor, malignant mixed Müllerian tumor, undifferentiated, and borderline). The investigation was based on immunohistochemical examination, performed by using specific antibodies applied on blocks obtained through Tissue MicroArray technique, and interpreted by scores assessing the nuclear positivity of tumoral cells. One case was not valuable due to technical difficulties. PAX8 expression was positive in 70 (81.39%) cases, the remaining 15 (17.44%) negative cases suggesting a non-Müllerian origin. WT1 expression was positive in 61 (71%) cases, mainly expressed in serous carcinoma, regardless of their differentiation degree, and negative in 24 (27%) cases. Our study provide supplementary evidences to support the association of PAX8 and WT1 immunostaining in the investigation of the complex biology of OC, PAX8 confirming the ovarian primary and WT1 allowing the refinement of the diagnosis in phenotype overlapping cases.

Stem cell-derived inner ear sensory epithelia are a promising source of tissues for treating patients with hearing loss and dizziness. We recently demonstrated how to generate inner ear sensory epithelia, designated as inner ear organoids, from mouse embryonic stem cells (ESCs) in a self-organizing 3D culture. Here we improve the efficiency of this culture system by elucidating how Wnt signaling activity can drive the induction of otic tissue. We found that a carefully timed treatment with the potent Wnt agonist CHIR99021 promotes induction of otic vesicles-a process that was previously self-organized by unknown mechanisms. The resulting otic-like vesicles have a larger lumen size and contain a greater number of Pax8/Pax2-positive otic progenitor cells than organoids derived without the Wnt agonist. Additionally, these otic-like vesicles give rise to large inner ear organoids with hair cells whose morphological, biochemical and functional properties are indistinguishable from those of vestibular hair cells in the postnatal mouse inner ear. We conclude that Wnt signaling plays a similar role during inner ear organoid formation as it does during inner ear development in the embryo.

Clear cell renal cell carcinoma (ccRCC) is characterized by BAP1 and PBRM1 mutations, which are associated with tumors of different grade and prognosis. However, whether BAP1 and PBRM1 loss causes ccRCC and determines tumor grade is unclear. We conditionally targeted Bap1 and Pbrm1 (with Vhl) in the mouse using several Cre drivers. Sglt2 and Villin proximal convoluted tubule drivers failed to cause tumorigenesis, challenging the conventional notion of ccRCC origins. In contrast, targeting with PAX8, a transcription factor frequently overexpressed in ccRCC, led to ccRCC of different grades. Bap1-deficient tumors were of high grade and showed greater mTORC1 activation than Pbrm1-deficient tumors, which exhibited longer latency. Disrupting one allele of the mTORC1 negative regulator, Tsc1, in Pbrm1-deficient kidneys triggered higher grade ccRCC. This study establishes Bap1 and Pbrm1 as lineage-specific drivers of ccRCC and histologic grade, implicates mTORC1 as a tumor grade rheostat, and suggests that ccRCCs arise from Bowman capsule cells.Significance: Determinants of tumor grade and aggressiveness across cancer types are poorly understood. Using ccRCC as a model, we show that Bap1 and Pbrm1 loss drives tumor grade. Furthermore, we show that the conversion from low grade to high grade can be promoted by activation of mTORC1. Cancer Discov; 7(8); 900-17. ©2017 AACR.See related commentary by Leung and Kim, p. 802This article is highlighted in the In This Issue feature, p. 783.

Molecular fine-needle aspiration (FNA) cytology diagnostics has the potential to address the inherent limitation of FNA cytology which is an indeterminate (atypia of undetermined significance/follicular lesion of undetermined significance follicular neoplasm) cytology. Because of the emerging role of molecular FNA cytology diagnostics, the European Thyroid Association convened a panel of international experts to review methodological aspects, indications, results, and limitations of molecular FNA cytology diagnostics. The panel reviewed the evidence for the diagnostic value of mutation panel assessment (including at least BRAF, NRAS, HRAS, KRAS, PAX8/PPARG, RET/PTC) of targeted next generation sequencing and of a microarray gene expression classifier (GEC) test in the diagnostic assessment of an indeterminate cytology thyroid nodule. Moreover, possible surgical consequences of molecular FNA diagnostic results of thyroid nodules and the evidence that analysis of a molecular FNA diagnostic panel of somatic mutations or a microarray GEC test can alter the follow-up were reviewed. Molecular tests may help clinicians to drive patient care and the surgical decision if the analysis is performed in specialized laboratories. These molecular tests require standardization of performance characteristics and appropriate calibration as well as analytic validation before clinical interpretation.

Thyroid cancer derived from follicular cells (TCDFC) comprises well-differentiated (papillary and follicular) carcinoma, poorly differentiated carcinoma, and anaplastic carcinoma. Papillary thyroid carcinoma is the most common endocrine cancer, and its incidence is steadily increasing. Lethality and aggressiveness of TCDFC is inversely correlated with differentiation degree. In this review, an emphasis has been put on molecular markers involved in tumorigenesis of thyroid carcinoma with a focus on aggressive histotypes and the role of such biomarkers in predicting thyroid cancer outcome. Genetic rearrangements in TCDFC (RET/PTC, PAX8/PPARG) and mutations in RAS, BRAF, TERT promoter (TERTp), TP53, PIK3CA, and AKT1 are discussed. The majority of the studies to date indicate that TERTp mutations can serve as a marker of more aggressive disease in all the subtypes of thyroid carcinoma, being the best current marker of poor prognosis, due to its independent association with distant metastases and increased disease-specific mortality. Some studies suggested that a more accurate prediction of thyroid cancer outcome may be possible through a more extensive genetic analysis. The same is true concerning the identification of other mutations that are only relatively frequent in advanced tumors (e.g., TP53, PIK3CA, or AKT1). A better understanding of the prognostic role of TERTp mutation (together with additional ones like BRAF, RAS, PIK3CA, AKT1, or TP53) and the clarification of their putative role in fine-needle aspiration biopsies are likely to allow, in the future, an early refinement of the stratification risk in patients with well-differentiated carcinomas. It is worth noting that, as with any categorical staging system, the risk evaluation within each category (low, intermediate, and high) varies depending on the specific clinicopathologic features of individual patients and the specific biological behavior of the tumor. Finally, besides the diagnostic and/or prognostic significance of the above-mentioned mutations, it is crucial to understand that the molecular pathways and epigenetic alterations will likely turn into interesting targets for new therapies.

Paired-box gene 8 (PAX8) encodes a transcription factor associated with important roles in embryogenesis and disease, and is a member of the PAX gene family. PAX8 has been demonstrated to be crucial in determining cell fate during the development of the thyroid, kidney, brain, eyes and Müllerian system and regulates expression of the Wilms' tumor suppressor gene (WT1). Several previous studies have reported that PAX8 is expressed at high levels in specific types of tumor, including thyroid and renal carcinomas and pancreatic neuroendocrine tumors. In addition, PAX8 has been reported to be useful for the detection and differential diagnosis of ovarian carcinoma. The consistency of PAX8 staining in epithelial ovarian carcinomas (EOCs) and the fallopian tube has provided morphological evidence that EOC may originate from the fallopian tube. The molecular mechanism of PAX8 in the carcinogenesis of these tumors remains unclear and requires further studies.

Loss-of-function mutations of the PAX8 gene are considered to mainly cause congenital hypothyroidism (CH) due to thyroid hypoplasia. However, some patients with PAX8 mutation have demonstrated a normal-sized thyroid gland. Here we report a CH patient caused by a PAX8 mutation, which manifested as iodide transport defect (ITD). Hypothyroidism was detected by neonatal screening and L-thyroxine replacement was started immediately. Although (123)I scintigraphy at 5 years of age showed that the thyroid gland was in the normal position and of small size, his iodide trapping was low. The ratio of the saliva/plasma radioactive iodide was low. He did not have goiter; however laboratory findings suggested that he had partial ITD. Gene analyses showed that the sodium/iodide symporter (NIS) gene was normal; instead, a mutation in the PAX8 gene causing R31H substitution was identified. The present report demonstrates that individuals with defective PAX8 can have partial ITD, and thus genetic analysis is useful for differential diagnosis.

Expression of L1 cell adhesion molecule (L1CAM) occurs frequently in human cancers and is associated with poor prognosis in cancers such as ovarian, endometrial, breast, renal cell carcinoma and pancreatic ductal adenocarcinoma. L1CAM promotes cell motility, invasion, chemoresistance and metastasis formation. Elucidating genetic processes involved in the expression of L1CAM in cancers is of considerable importance. Transcription factors such as SLUG, β-catenin/TCF-LEF, PAX8 and VHL have been implicated in the re-activation of L1CAM in various types of cancers. There is increasing evidence that micro-RNAs can also have strong effects on gene expression. Here we have identified miR-21-3p as a positive regulator of L1CAM expression. Over-expression of miR-21-3p (miR-21*) but not the complementary sequence miR-21-5p (miR-21) could strongly augment L1CAM expression in renal, endometrial and ovarian carcinoma derived cell lines by an unknown mechanism involving transcriptional activation of the L1CAM gene. In patient cohorts from renal, endometrial and ovarian cancers we observed a strong positive correlation of L1CAM and miR-21-3p expressions. Although L1CAM alone was a reliable marker for overall and disease free survival, the combination of L1CAM and miR-21-3p expressions strongly enhanced the predictive power. Our findings shed new light on the complex regulation of L1CAM in cancers and advocate the use of L1CAM/miR-21-3p for diagnostic application.

Famine exposure in utero can 'programme' an individual towards type 2 diabetes and obesity in later life. We sought to identify, (1) whether Bangladeshis exposed to famine during developmental life are programmed towards diabetes and obesity, (2) whether this programming was specific to gestational or postnatal exposure windows and (3) whether epigenetic differences were associated with famine exposure.

A historical cohort study was performed as part of a wider cross-sectional survey. Exposure to famine was defined through birth date and historical records and participants were selected according to: (A) exposure to famine in postnatal life, (B) exposure to famine during gestation and (C) unexposed.

Matlab, a rural area in the Chittagong division of Bangladesh.

Young adult men and women (n=190) recruited to a historical cohort study with a randomised subsample included in an epigenetic study (n=143).

Primary outcome measures of weight, body mass index and oral glucose tolerance tests (0 and 120 min glucose). Secondary outcome measures included DNA methylation using genome-wide and targeted analysis of metastable epialleles sensitive to maternal nutrition.

More young adults exposed to famine in gestation were underweight than those postnatally exposed or unexposed. In contrast, more young adults exposed to famine postnatally were overweight compared to those gestationally exposed or unexposed. Underweight adults exposed to famine in gestation in utero were hyperglycaemic following a glucose tolerance test, and those exposed postnatally had elevated fasting glucose, compared to those unexposed. Significant differences in DNA methylation at seven metastable epialleles (VTRNA2-1, PAX8, PRDM-9, near ZFP57, near BOLA, EXD3) known to vary with gestational famine exposure were identified.

Famine exposure in developmental life programmed Bangladeshi offspring towards diabetes and obesity in adulthood but gestational and postnatal windows of exposure had variable effects on phenotype. DNA methylation differences were replicated at previously identified metastable epialleles sensitive to periconceptual famine exposure.

The cell-of-origin of high grade serous ovarian carcinoma (HGSOC) remains controversial, with fallopian tube epithelium (FTE) and ovarian surface epithelium (OSE) both considered candidates. Here, by using genetically engineered mouse models and organoids, we assessed the tumor-forming properties of FTE and OSE harboring the same oncogenic abnormalities. Combined RB family inactivation and Tp53 mutation in Pax8 + FTE caused Serous Tubal Intraepithelial Carcinoma (STIC), which metastasized rapidly to the ovarian surface. These events were recapitulated by orthotopic injection of mutant FTE organoids. Engineering the same genetic lesions into Lgr5 + OSE or OSE-derived organoids also caused metastatic HGSOC, although with longer latency and lower penetrance. FTE- and OSE-derived tumors had distinct transcriptomes, and comparative transcriptomics and genomics suggest that human HGSOC arises from both cell types. Finally, FTE- and OSE-derived organoids exhibited differential chemosensitivity. Our results comport with a dualistic origin for HGSOC and suggest that the cell-of-origin might influence therapeutic response.

Vertebrate sensory organs develop in part from cranial placodes, a series of ectodermal thickenings that coalesce from a common domain of preplacodal ectoderm. Mechanisms coordinating morphogenesis and differentiation of discrete placodes are still poorly understood. We have investigated whether placodal assembly in zebrafish requires Integrin- α5 (itga5), an extracellular matrix receptor initially expressed throughout the preplacodal ectoderm. Morpholino knockdown of itga5 had no detectable effect on anterior placodes (pituitary, nasal and lens), but posterior placodes developed abnormally, resulting in disorganization of trigeminal and epibranchial ganglia and reduction of the otic vesicle. Cell motion analysis in GFP-transgenic embryos showed that cell migration in itga5 morphants was highly erratic and unfocused, impairing convergence and blocking successive recruitment of new cells into these placodes. Further studies revealed genetic interactions between itga5 and Fgf signaling. First, itga5 morphants showed changes in gene expression mimicking modest reduction in Fgf signaling. Second, itga5 morphants showed elevated apoptosis in the otic/epibranchial domain, which was rescued by misexpression of Fgf8. Third, knockdown of the Fgf effector erm had no effect by itself but strongly enhanced defects in itga5 morphants. Finally, proper regulation of itga5 requires dlx3b/4b and pax8, which are themselves regulated by Fgf. These findings support a model in which itga5 coordinates cell migration into posterior placodes and augments Fgf signaling required for patterning of these tissues and cell survival in otic/epibranchial placodes.

BACKGROUND

In vertebrates, the primordium of the brain is subdivided by the expression of Otx genes (forebrain/anterior midbrain), Hox genes (posterior hindbrain), and the genes Pax2, Pax5 and Pax8 (intervening region). The latter includes the midbrain/hindbrain boundary (MHB), which acts as a key organizer during brain patterning. Recent studies in Drosophila revealed that orthologous sets of genes are expressed in a similar tripartite pattern in the late embryonic brain, which suggested correspondence between the Drosophila deutocerebral/tritocerebral boundary region and the vertebrate MHB. To gain more insight into the evolution of brain regions, and particularly the MHB, I examined the expression of a comprehensive array of MHB-specific gene orthologs in the procephalic neuroectoderm and in individually identified neuroblasts during early embryonic stages 8-11, at which the segmental organization of the brain is most clearly displayed.

CONCLUSIONS

I show that the early embryonic brain exhibits an anterior Otx/otd domain and a posterior Hox1/lab domain, but that Pax2/5/8 orthologs are not expressed in the neuroectoderm and neuroblasts of the intervening territory. Furthermore, the expression domains of Otx/otd and Gbx/unpg exhibit a small common interface within the anterior deutocerebrum. In contrast to vertebrates, Fgf8-related genes are not expressed posterior to the otd/unpg interface. However, at the otd/unpg interface the early expression of other MHB-specific genes (including btd, wg, en), and of dorsoventral patterning genes, closely resembles the situation at the vertebrate MHB. Altogether, these results suggest the existence of an ancestral territory within the primordium of the deutocerebrum and adjacent protocerebrum, which might be the evolutionary equivalent of the region of the vertebrate MHB. However, lack of expression of Pax2/5/8 and Fgf8-related genes, and significant differences in the expression onset of other key regulators at the otd/unpg interface, imply that genetic interactions crucial for the vertebrate organizer activity are absent in the early embryonic brain of Drosophila.