Background: Gene panels are routinely used to assess predisposition to hereditary cancers by simultaneously testing multiple susceptibility genes and/or variants. More recently, genetic panels have been implemented as part of solid tumor malignancy testing assessing somatic alterations. One example is targeted variant panels for thyroid nodules that are not conclusively malignant or benign upon fine-needle aspiration (FNA). We systematically reviewed published studies from 2009 to 2018 that contained genetic data from preoperative FNA specimens on cytologically indeterminate thyroid nodules (ITNs) that subsequently underwent surgical resection. Pooled prevalence estimates per gene and variant, along with their respective positive predictive values (PPVs) for malignancy, were calculated. Summary: Our systematic search identified 540 studies that were supplemented by 18 studies from bibliographies or personal files. Sixty-one studies met all inclusion criteria and included >4600 ITNs. Overall, 26% of nodules contained at least 1 variant or fusion. However, half of them did not include details on the specific gene, variant, and/or complete fusion pair reported for inclusion toward PPV calculations. The PPVs of genomic alterations reported at least 10 times were limited to BRAF^V600E (98%, 95% confidence interval [CI 96-99%]), PAX8/PPARG (55% [CI 34-78%]), HRAS^Q61R (45% [CI 22-72%]), BRAF^K601E (42% [CI 19-68%]), and NRAS^Q61R (38% [CI 23-55%]). Excluding BRAF^V600E, the pooled PPV for all other specified variants and fusions was 47%. Multiple variants within the same nodule were identified in ∼1% of ITN and carried a cumulative PPV of 77%. Conclusions: The chance that a genomic alteration predicts malignancy depends on the individual variant or fusion detected. Only five alterations were reported at least 10 times; BRAF^V600E had a PPV of 98%, while the remaining four had individual PPVs ranging from 38% to 55%. The small sample size of most variants and fusion pairs found among ITNs, however, limits confidence in their individual PPV point estimates. Better specific reporting of genomic alterations with cytological category, histological subtype, and cancer staging would facilitate better understanding of cancer prediction, and the independent contribution of the genomic profile to prognosis.

Molecular markers associated with thyroid malignancy are increasingly being used as differential diagnostic tools for thyroid nodules. However, little has been reported recently regarding the prevalence of these markers in benign lesions. The literature was systematically reviewed to examine studies that reported on the prevalence of these markers in benign thyroid lesions.

Appropriate studies published between January 1, 2000, and April 30, 2015, and cataloged in PubMed, Embase, Cochrane, Scopus, and Web of Science databases were searched for by combining different keywords for "thyroid tumor" with both general and specific keywords for "molecular marker" by using "AND" as the Boolean operator. All studies meeting criteria that reported the prevalence of RAS mutations, and RET/PTC and PAX8/PPAR-gamma chromosomal rearrangements in benign thyroid lesions were included for study.

A total of 64 articles (including 8162 patients, of whom 42.5% had benign lesions) that met all the study criteria were systematically reviewed and abstracted. Among 35 studies examining RAS mutations, the reported prevalence of RAS mutation in benign lesions ranged from 0% to 48%. In 38 studies examining RET/PTC rearrangements, the prevalence in benign lesions ranged from 0% to 68%. PAX8/PPAR-gamma rearrangements were examined in 27 studies, with the prevalence in benign lesions ranging from 0% to 55%.

The presence of these biomarkers and the tremendous variation in reports of their prevalence in benign lesions suggests the need for caution when including these markers in diagnostic decisions. Further understanding of the importance of these markers, as well as newly discovered markers of thyroid malignancy, may be required in order to avoid overtreatment of patients with benign thyroid tumors.

Background: High-grade serous ovarian cancer (HGSOC) is a major unmet need in oncology. The remaining uncertainty on its originating tissue has hampered the discovery of molecular oncogenic pathways and the development of effective therapies.

Methods: We used an approach based on the retention in tumors of a DNA methylation trace (OriPrint) that distinguishes the two putative tissues of origin of HGSOC, the fimbrial (FI) and ovarian surface epithelia (OSE), to stratify HGSOC by several clustering methods, both linear and non-linear. The identified tumor subtypes (FI-like and OSE-like HGSOC) were investigated at the RNAseq level to stratify an in-house cohort of macrodissected HGSOC FFPE samples to derive overall and disease-free survival and identify specific transcriptional alterations of the two tumor subtypes, both by classical differential expression and weighted correlation network analysis. We translated our strategy to published datasets and verified the co-occurrence of previously described molecular classification of HGSOC. We performed cytokine analysis coupled to immune phenotyping to verify alterations in the immune compartment associated with HGSOC. We identified genes that are both differentially expressed and methylated in the two tumor subtypes, concentrating on PAX8 as a bona fide marker of FI-like HGSOC.

Results: We show that: - OriPrint is a robust DNA methylation tracer that exposes the tissue of origin of HGSOC. - The tissue of origin of HGSOC is the main determinant of DNA methylation variance in HGSOC. - The tissue of origin is a prognostic factor for HGSOC patients. - FI-like and OSE-like HGSOC are endowed with specific transcriptional alterations that impact patients' prognosis. - OSE-like tumors present a more invasive and immunomodulatory phenotype, compatible with its worse prognostic impact. - Among genes that are differentially expressed and regulated in FI-like and OSE-like HGSOC, PAX8 is a bona fide marker of FI-like tumors.

Conclusions: Through an integrated approach, our work demonstrates that both FI and OSE are possible origins for human HGSOC, whose derived subtypes are both molecularly and clinically distinct. These results will help define a new roadmap towards rational, subtype-specific therapeutic inroads and improved patients' care.

PAX8 is a thyroid-specific transcription factor whose expression is dysregulated in thyroid cancer. A recent study using a conditional knock-out mouse model identified 58 putative PAX8 target genes. In the present study, we evaluated the expression of 11 of these genes in normal and tumoral thyroid tissues from patients with papillary thyroid cancer (PTC). ATP1B1, GPC3, KCNIP3, and PRLR transcript levels in tumor tissues were significantly lower in PTCs than in NT, whereas LCN2, LGALS1 and SCD1 expression was upregulated in PTC compared with NT. Principal component analysis of the expression of the most markedly dysregulated PAX8 target genes was able to discriminate between PTC and NT. Immunohistochemistry was used to assess levels of proteins encoded by the two most dyregulated PAX8 target genes, LCN2 and GPC3. Interestingly, GPC3 was detectable in all of the NT samples but none of the PTC samples. Collectively, these findings point to significant PTC-associated dysregulation of several PAX8 target genes, supporting the notion that PAX8-regulated molecular cascades play important roles during thyroid tumorigenesis.

Ovarian cancer is considered the leading cause of death among gynecologic neoplasias. Breast metastases from primary ovarian cancer have been reported in only 0.03-0.6% of all breast cancers. A 38-year-old female, multipara, affected by advanced ovarian cancer and undergone a total abdominal hysterectomy with bilateral salpingo-oophorectomy, omentectomy, and pelvic peritonectomy two years earlier, was discovered to have a breast metastasis. She underwent a quadrantectomy (QSI) with an open biopsy of nodularity attached to the pectoral muscle fascia: on definitive histological characterization the breast lesions showed a high-grade invasive carcinoma, with papillary serum differentiation, and the immunohistochemistry study of breast lesion showed positivity for cytokeratin 7 and an extensive positivity for Wilm's tumor (WT)-1 and paired box 8 (PAX8). These aspects are indicative of mammary metastasis from carcinoma of ovarian origin. Despite their rarity, metastases to breast from ovarian cancer should be considered possible because their recognition and differentiation compared to primary tumors are crucial for prognosis. Future clinical studies on MOCB should be performed to discover new specific markers for a more accurate histopathological diagnosis and to establish the real need of surgical treatment.

A chromosomal translocation results in production of an oncogenic PAX8-PPARG fusion protein (PPFP) in thyroid carcinomas. PAX8 is a thyroid transcription factor, and PPARG is a transcription factor that plays important roles in adipocytes and macrophages. PPFP retains the DNA binding domains of both proteins; however, the genomic binding sites of PPFP have not been identified, and only limited data exist to characterize gene expression in PPFP thyroid carcinomas. Therefore, the oncogenic function of PPFP is poorly understood. We expressed PPFP in PCCL3 rat thyroid cells and used ChIP-seq to identify PPFP genomic binding sites (PPFP peaks) and RNA-seq to characterize PPFP-dependent gene expression. PPFP peaks (~20,000) include known PAX8 and PPARG binding sites and are enriched with both motifs, indicating that both DNA binding domains are functional. PPFP binds to and regulates many genes involved in cancer-related processes. In PCCL3 thyroid cells, PPFP binds to adipocyte PPARG target genes in preference to macrophage PPARG target genes, consistent with the pro-adipogenic nature of PPFP and its ligand pioglitazone in thyroid cells. PPFP induces oxidative stress in thyroid cells, and pioglitazone increases susceptibility to further oxidative stress. Our data highlight the complexity of PPFP as a transcription factor and the numerous ways that it regulates thyroid oncogenesis.

Upper urinary tract urothelial cell carcinomas (UUT-UCs) are uncommon and are defined as urothelial carcinoma involving the urinary tract from the renal calyces, renal pelvis to the distal ureter. One well-known an peculiar histopathological finding in UUT-UC is urothelial carcinoma with intratubular spread (retrograde spread within renal tubules). However, this special feature has not been systematically studied. We therefore collected a total of 53 consecutive cases of upper urinary tract urothelial carcinomas (UUT-UCs), and studied the clinical and pathological features of intratubular spread (IS). A cocktail stain comprised of antibodies PAX8 and p63 together with PAS was validated and employed to facilitate the study of intratubular spread. Seventeen cases (31.5%) showed intratubular spread demonstrated by either H&E stain and/or the cocktail stain. All of the 17 cases wit intratubular spread had tumor involvement of the renal calyx; the majority of these (14/17, 82.4%) were high grade urothelial carcinoma and the remainder (3/17, 17.6%) were low grade. 4 of 17cases (23.5%) were non-invasive. We classified intratubular spread into 4 different types, based on histopathological patterns: pagetoid, typical, florid, and secondary invasion from intratubular spread. In conclusion, study shows intratubular spread of urothelial carcinoma is fairly common phenomenon in UUT-UC and is associated with a variety of clinical-pathological features. High grade UUT-UC tends to have more extensive intratubular spread and secondary invasion into renal parenchyma. Distinct morphological characteristics as well as the staining pattern from a unique cocktail stain help to identify and evaluate intratubular spread of urothelial carcinoma. Recognizing these different types of intratubular spreading (IS) is crucial for accurate staging of some upper urinary tract urothelial carcinomas (UUT-UCs).

Reports of interstitial deletions involving proximal long arm of chromosome 2 are limited. Based on early chromosomal analysis studies, the phenotypic consequence of deletions at the ancestral chromosome fusion site at chromosome 2q13q14.1 remains unclear. A recurrent 1.71 Mb deletion at 2q13 has recently been proposed as a new genomic disorder, associated with an increased risk of intellectual disability and craniofacial dysmorphism. Herein, we report the case of a 12 year-old girl with unique clinical features including global developmental delay, mullerian agenesis, and hypothyroidism associated with a normal size and position of the thyroid gland, as well as negative thyroid antibodies. Microarray-based comparative genomic hybridization study revealed a de novo 10.79 Mb deletion at 2q13q14.2 (111,548,932-122,336,492), which involves more than 88 UCSC genes, 38 of which are OMIM genes, 7 of which are disease-causing and 3 of which (including GLI2, IL1B and PAX8) show a dominant inheritance pattern.. Interestingly, PAX8 (chr2:113,973,574-114,036,498), a member of the paired-box gene family, is essential for the formation of thyroxine-producing follicular cells. Autosomal dominant transmission of congenital thyroid hypoplasia due to loss-of-function mutation of PAX8 suggests a possible haploinsufficiency effect. Additionally, PAX8 is also expressed in the tissue primordia that form both the mullerian duct derivatives and the upper urinary tracts. A recent study has associated a novel PAX8 mutation with a severe form of hypothyroidism and abnormalities in the urogenital tract. Taken together, the unique clinical manifestation seen in this patient could be attributed to the heterozygous deletion of PAX8 gene. A prospective investigation is merited to fully evaluate the pathogenic effect of the interstitial deletion of 2q13q14.2.

Congenital hypothyroidism is the principle cause of preventable mental retardation, with a prevalence of 1 in 3,500 neonates. The disorder may be permanent or transitory. Permanent congenital hypothyroidism is caused principally by thyroid dysgenesis. In industrialized countries, mass screening allows the disorder to be diagnosed at birth. The severity is variable but is generally more pronounced in females. The majority of studies point to a genetic origin for the disease and no consistent evidence has been found to suggest a major role for environmental factors. The genetic factors have already been identified and involve several elements (mutations in the TTF-1, TTF-2, PAX8 and TSH receptor genes). The etiological diagnosis is based on scintigraphy, ultrasound and the level of circulating thyroglobulin. At present, treatment is administered at an adapted dose during the first two weeks of life and should allow the child to reach its full intellectual potential. However, minor anomalies have been reported in some treated children, suggesting that this treatment cannot compensate for a certain degree of foetal hypothyroidism.

After a couple of decades from the institution of nationwide congenital hypothyroidism (CH) newborn screening program, the first generation properly treated is now displaying normal reproductive rate and the causative molecular defects are spreading from one generation to the next. In the present study we propose a method of detection of mutations in the thyrotropin receptor (TSHR) and in the paired box 8 (PAX8) genes that have been proved to be responsible for some forms of CH. The method, carried out by means of denaturing high-performance liquid chromatography (DHPLC) followed by direct sequencing, takes advantage of the CH newborn screening procedure, because genomic DNA for the analysis is extracted from the same blood spot collected for recall confirmation. Among 16 hypothyroid newborns with thyroid hypoplasia born between January 1999 and April 2005 in northeastern Italy, three heterozygous causative mutations in the TSHR gene were evidenced, whereas the analysis of the PAX8 gene revealed an unknown heterozygous substitution that could interfere with the start of transcription.

Thyroid-like follicular carcinoma of the kidney (TLFCK) is a rare but emerging renal neoplasm that morphologically mimics follicular carcinoma of the thyroid but lacks immunohistochemical expression of thyroid markers such as TTF-1 and thyroglobulin. Here, a case of an incidentally discovered TLFCK in a 27-year-old man is reported. Histologic evaluation demonstrated an encapsulated proliferation of variably sized thyroid follicle-like epithelial-lined spaces filled with colloid-like eosinophilic secretions. Immunohistochemical analysis confirmed lack of expression of the thyroid markers TTF-1 and thyroglobulin with expression of PAX8 and CD10, confirming a neoplasm of renal origin, which correlated to the clinical and radiographic absence of thyroid pathology. In this report, this case is described with an emphasis on the differential diagnosis.

Objective: Diabetic nephropathy (DN), the microvascular complications of diabetes, is one of the world's public health hazard. But the detailed mechanism of the occurrence and development remains unclear. Oxidative stress caused by multiple factors is recognized as the main cause of disease, and it is also a research focus. Recently, long non-coding RNAs (lncRNAs) have been declared to involve in a large of important bioactivities in many different diseases. In our study, we aimed to verify whether lncRNA PAX8-AS1-N involved in protecting podocyte apoptosis and directly associated with VEGF/TGF-β1/8-OhdG levels in DN, and further investigated the detailed mechanism that PAX8-AS1-N regulated the pathological process.

Materials and methods: We used blood and urine samples of DN patients to detect the expression of lncRNA-PAX8-AS1-N and VEGF/TGF-β1/8-OhdG by ELISA and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Albuminuria level, relative PAX8-AS1-N and VEGF/TGF-β1/8-OhdG levels, and VEGF/TGF-β1/8-OhdG and cleaved-caspase-3 protein levels were detected by ELISA, qRT-PCR, and Western blot, respectively. CCK8 assay was used to measure the proliferation ability of conditionally immortalized mouse podocytes (MPC5). And we used the TUNEL assay to detect MPC5 apoptosis. Luciferase reporter assay was used to confirm the direct target of PAX8-AS-N and miR-17-5p in MPC5.

Results: We found that the lncRNA PAX8-AS1-N was lowly expressed and high expression of VEGF/TGF-β1/8-OhdG and high level of albuminuria in DN patients and high-glucose-treated MPC5. Besides, we proved that LV-PAX8-AS1-N decreased MPC5 apoptosis and suppressed the expression of VEGF/TGF-β1/8-OhdG in vitro experiment. At last, the overexpression of miR-17-5p markedly induced cell apoptosis in MPC5 with high glucose (HG) model. STAT3 reverses the effects of miR-17-5p overexpression in MPC5 with HG model.

Conclusions: Above that, we found that lncRNA PAX8-AS1-N/miR-17-5p/STAT3 axis was closely related the progression of DN, which could be a potential target for treating DN patients.

As a common malignancy of the endocrine system, papillary thyroid carcinoma (PTC) seriously affects the quality of life of patients. lncRNA PAX8‑AS1:28, or lnc‑PSD4‑1:14 has been reported to be abnormally expressed in PTC. However, the function of PAX8‑AS1:28 in PTC is still unknown. Therefore, the present study aimed to investigate the functions of PAX8‑AS1:28 in PTC, and to explore the possible mechanisms of action. A total of 38 patients with PTC were included and the normal thyroid follicular epithelial cell line Nthy‑ori 3‑1 and PTC cell line IHH‑4 were also used. MYC and PAX8‑AS1:28 overexpression and siRNA silencing in the cell lines were carried out. Expression of PAX8‑AS1:28, PAX8 and MYC in tumor tissue, adjacent healthy tissue and different cell lines were detected by qRT‑PCR and western blot analysis. Cell proliferation was measured by CCK‑8 assay. Expression levels of PAX8‑AS1:28 and PAX8 were lower in PTC tumor tissue and PTC cells than those in healthy tissue and normal cells. In contrast, the expression level of MYC was higher in PTC cells than that in normal cells. PAX8‑AS1:28 silencing reduced the expression level of PAX8 and promoted tumor cell growth, while PAX8‑AS1:28 overexpression increased the expression level of PAX8 and inhibited tumor cell growth. MYC silencing increased expression levels of PAX8‑AS1:28 and PAX8 and inhibited tumor cell growth, while MYC overexpression decreased expression levels of PAX8‑AS1:28 and PAX8 and promoted tumor cell growth. MYC can promote PTC by inhibiting the expression of lncRNA PAX8‑AS1:28.

Rhabdomyosarcoma (RMS) is a pediatric tumor, which arises from muscle precursor cells. Recently, it has been demonstrated that Hippo Pathway (Hpo), a pathway that regulates several physiological and biological features, is involved in RMS tumorigenesis. For instance, an upregulation of the Hpo downstream effector Yes-Associated Protein 1 (YAP) leads to the development of embryonal rhabdomyosarcoma (eRMS) in murine activated muscle satellite cells. On the other hand, the YAP paralog transcriptional co-activator with PDZ-binding motif (TAZ) is overexpressed in alveolar rhabdomyosarcoma (aRMS) patients with poor survival. YAP and TAZ exhibit both cytoplasmic and nuclear functions. In the nucleus, YAP binds TEADs (TEA domain family members) factors and together they constitute a complex that is able either to activate the transcription of several genes such as MYC, Tbx5 and PAX8 or to maintain the stability of others like p73. Due to the key role of YAP and TAZ in cancer, the identification and/or development of new compounds able to block their activity might be an effective antineoplastic strategy. Verteporfin (VP) is a molecule able to stop the formation of YAP/TEAD complex in the nucleus. The aim of this study is to evaluate the action of VP on RMS cell lines. This work shows that VP has an anti-proliferative activity on all RMS cell lines analyzed. Depending on RMS cell lines, VP affects cell cycle differently. Moreover, VP is able to decrease YAP protein levels, and to induce the activation of apoptosis mechanism through the cleavage of PARP-1. In addition, Annexin V assay showed the activation of apoptosis and necrosis after VP treatment. In summary, the ability of VP to disrupt RMS cell proliferation could be a novel and valuable strategy to improve the therapeutic approaches in treating rhabdomyosarcoma.

Recently cabozantinib, a tyrosine kinase inhibitor with activity against VEGF, MET, AXL, and downregulating cathepsin K in vitro, has been proposed for the treatment of advanced clear and non-clear renal cell carcinomas. Since it is well known that cathepsin K is expressed in the majority of MiT family translocation renal cell carcinomas, we investigated cathepsin K, MET, AXL, and VEGF in a large series of those tumours, looking for possible predictive markers. We collected the clinicopathological features of 34 genetically confirmed MiT family translocation renal cell carcinomas [26 Xp11 and 8 t(6;11) renal cell carcinomas] and studied them using an immunohistochemical panel including PAX8, cathepsin K, HMB45, Melan-A, CD68 (PG-M1), CK7, CA9, MET, AXL and by FISH for VEGFA and MET. Cathepsin K was expressed in 14 of 26, HMB45 in 8 of 25, and Melan-A in 4 of 23 Xp11 renal cell carcinomas, whereas labelling for CK7 and CA9 was minimal. In t(6;11) renal cell carcinoma, cathepsin K and melanogenesis markers were constantly positive, whereas CK7 and CA9 were negative. None of the 34 carcinomas showed CD68 (PG-M1) and AXL expression. One aggressive Xp11 renal cell carcinoma showed increased VEGFA gene copy number (4-5 copies) with concurrent gains of TFE3 and TFEB. None of the 34 carcinomas showed MET gene amplification, whereas staining for MET was found in 7 of 8 t(6;11) and in 16 of 24 Xp11 renal cell carcinomas, and in the latter cases, when the expression was >50%, correlated with aggressiveness (p=0.0049). In Xp11 renal cell carcinomas, the aggressiveness was also correlated with larger tumour size (p=0.0008) and the presence of necrosis (p=0.027) but not nucleolar grading (p=1). Interestingly, in patients with tumours exhibiting two of three parameters (necrosis, larger tumour size and MET immunolabelling >50%) an aggressive clinical behaviour was observed in 88% of cases. In conclusion, cathepsin K, CD68 (PG-M1), CK7, CA9, and PAX8 is a useful panel for the diagnosis. Larger tumour size, the presence of necrosis and MET immunohistochemical expression correlate with aggressive behaviour in Xp11 renal cell carcinomas, especially in combination. VEGF, MET, cathepsin K but not AXL may be potential predictive markers for targeted therapy in MiT family translocation renal cell carcinomas.

BACKGROUND

To better define the cytomorphologic spectrum of endosalpingiosis in peritoneal washings (PWs) and thereby facilitate their distinction from well differentiated serous carcinoma, the authors examined PWs from women who underwent surgery and pathologic staging of lesions other than Mullerian malignancies and correlated the findings with surgical specimens.

METHODS

This was a retrospective review of medical records and PW specimens from 100 consecutive patients who had PWs coded as both "endosalpingiosis" and "negative for carcinoma" between 2002 and 2012. Thirty-eight of these patients had no gynecologic malignancies. Specimens had been prepared using cytocentrifugation and were stained using the Papanicolaou method. The cytologic findings evaluated were cell arrangement, number of cell groups per case, cellular atypia, and psammoma bodies. Smears also were assessed for paired box-8 (PAX8) immunostaining. The authors compared patients' staging biopsy findings with the findings from a review of the PWs.

RESULTS

PW specimens from 35 of 38 patients (92%) exhibited classic endosalpingiosis features: tubular or small branching papillary structures, some with psammoma bodies. Specimens from the 3 remaining patients displayed nonclassic features consistent with dislodged fallopian tube epithelium or endometriosis. From 2 to 20 clusters per slide and from 4 to 50 groups per case were identified. In a few cases, some cell clusters exhibited up to moderate cytologic atypia. Surgical findings included endometriosis, endosalpingiosis, both endometriosis and endosalpingiosis (12 patients; 31.6%), and a variety of unrelated pelvic lesions. All cases were PAX8-positive, confirming their Mullerian origin.

CONCLUSIONS

Endosalpingiosis in PWs can be diagnostically challenging. Awareness of intraoperative techniques and correlation with surgical biopsy findings are necessary to avoid a misdiagnosis of malignancy.

Anaplastic thyroid cancer (ATC) is rare but extremely aggressive, which accounts for about 2% of all thyroid cancers yet nearly 50% of thyroid-cancer-associated deaths in the United States. The median survival time from diagnosis is 5 months, with a 1-year survival rate of only 20%. We report here a case of ATC in a 56-year-old man who survived a large ATC. Preoperative fine-needle aspiration biopsy study to a large right thyroid mass suggested ATC. Total thyroidectomy with radical lateral neck and central neck dissection removed a well-circumscribed 9.5 cm tumor without extrathyroidal extension or lymphovascular invasion. All 73 lymph nodes removed were negative for metastasis. The tumor consisted of highly pleomorphic, undifferentiated cells with large zones of necrosis and loss of thyroid transcription factor-1 and thyroglobulin expression. A focal well-differentiated component and PAX8 expression confirmed its thyroid follicular cell origin. Nine months after postsurgical adjuvant concurrent radiation therapy and chemotherapy, the patient remained well without clinical, biochemical, and radiographical evidence for cancer recurrence. This is an unusual case of ATC in that it is one of the largest ATC tumors reported to display mild pathologic behavior and relatively long-term patient survival.

BACKGROUND

Anaplastic thyroid carcinoma (ATC) is a rare, aggressive malignancy with a median survival of five months. Multimodality treatment is associated with some improvement in survival, but patients are only infrequently curable. Although β-hCG secretion has been reported in many neoplasms, it has never been described in ATC. The objectives of this study were to report a case of β-hCG-secreting ATC and to study the expression and significance of β-hCG and PAX8 in an institutional cohort of ATC.

METHODS

The sentinel case was characterized and then immunohistochemistry was performed for β-hCG and PAX8 on 30 ATC patients. Clinical follow-up was obtained by chart review.

RESULTS

The sentinel patient with β-hCG-secreting ATC had a dramatic response to chemotherapy and radiation. After surgical excision of residual disease, the patient developed a regional recurrence of differentiated thyroid carcinoma at 18 months. However, she is now, 30 months after initial therapy, with no evidence of disease and no detectable serum β-hCG or thyroglobulin. Five of the 30 (17%) total ATCs were positive for β-hCG and 18 (60%) for PAX8. Outcomes for the β-hCG-positive cases were not significantly different from those for negative ones. However, none of the other four β-hCG-positive ATC patients received treatment with either chemotherapy or radiation. Interestingly, PAX8 positivity correlated with statistically significantly better overall survival (p=0.019).

CONCLUSIONS

β-hCG is expressed in a minority of ATCs. Although only a single case in the study had diffuse immunohistochemical expression, the response it showed to aggressive multimodality therapy and the resulting favorable outcome suggest that β-hCG-positive ATC may be a unique tumor subtype, or possibly even a unique entity. PAX8 is a useful marker of ATC and may be helpful in the differential diagnosis with other malignant neoplasms.

Transcriptional mechanisms associated with iodide-induced downregulation of NIS expression remain uncertain. Here, we further analyzed the transcriptional regulation of NIS gene expression by excess iodide using PCCl3 cells. NIS promoter activity was reduced in cells treated for 12-24 h with 10(-5) to 10(-3) M NaI. Site-directed mutagenesis of Pax8 and NF-κB cis-acting elements abrogated the iodide-induced NIS transcription repression. Indeed, excess iodide (10(-3) M) excluded Pax8 from the nucleus, decreased p65 total expression and reduced their transcriptional activity. Importantly, p65-Pax8 physical interaction and binding to NIS upstream enhancer were reduced upon iodide treatment. PI3K/Akt pathway activation by iodide-induced ROS production is involved in the transcriptional repression of NIS expression. In conclusion, the results indicated that excess iodide transcriptionally represses NIS gene expression through the impairment of Pax8 and p65 transcriptional activity. Furthermore, the data presented herein described novel roles for PI3K/Akt signaling pathway and oxidative status in the thyroid autoregulatory phenomenon.

OBJECTIVE

It is difficult to diagnose anaplastic thyroid carcinoma (ATC) in a fine-needle aspiration (FNA) sample because, given the loss of morphological and immunophenotypical follicular thyroid features, its cytology resembles that of other undifferentiated neoplasms. Recent studies have shown that immunostaining for paired box gene 8 (PAX8), a transcription factor expressed in normal thyroid, is effective for diagnosing ATCs on histology. The aim of this study was to evaluate whether PAX8 could be used to identify ATCs on cytology also.

METHODS

We selected three PAX8-immunostained undifferentiated FNA samples previously diagnosed as suspected ATCs, whose cell block had been negative for the expression of TGB and thyroid transcription factor-1. Matched histological samples, available in two cases, were also processed for PAX8 immunohistochemistry.

RESULTS

All three FNA samples were PAX8 positive. Two samples that had an epithelioid pattern showed a diffuse, intense nuclear signal. The third sample, which had a spindle-cell pattern, showed less intense and more patchy staining. Matched histology yielded overlapping results.

CONCLUSIONS

PAX8 immunocytochemistry can help cytopathologists to diagnose ATCs.

PAX8 gene encodes one of the transcription factors engaged in the regulation of proper development of thyroid gland as well as Müllerian and renal/upper urinary tracts. So far, six alternatively spliced transcripts were reported, however, sequences of only four were deposited in the NCBI database. Here, we evaluate a fragment of a novel variant of PAX8 mRNA formed by an alternative 3' acceptor site located in the second exon. The molecular outcome encompasses extension of the 5' untranslated region of exon two by 97 nucleotides as is evident from mRNA. This new insert may impair binding of mRNA to the ribosome and in consequence significantly decrease expression of the PAX8 protein. Here, we show for the first time that the novel insert in exon two might be associated with congenital thyroid hemiagenesis and influence development of different types of cancer.