In a large Saudi Arabian family with hereditary hemorrhagic telangiectasia (HHT), we identified ACVRL1 (ALK1) nonsense mutation Q490X in 40 HHT patients and three healthy children, but neither in 11 individuals with epistaxis, 41 other healthy family members, nor in 50 healthy unrelated Saudi Arabian controls. Sequence analysis of the entire coding region of the ACVRL1 and ENG genes in five of the 11 epistaxic individuals did not reveal any other disease-causing mutation. Epistaxis seems to be a relatively common phenocopy of HHT in the family under study. One couple, both affected by HHT and carriers of Q490X, had 12 pregnancies. Three of them ended in spontaneous abortion, four in early neonatal death, and only five yielded living offspring, all of which had HHT and were Q490X heterozygous. This observation corroborates previous claims that homozygosity for HHT-causing mutations is lethal.

BACKGROUND

The hereditary hemorrhagic telangiectasia syndrome (HHT), also known as the Rendu-Osler-Weber syndrome is a multiorganic vascular disorder inherited as an autosomal dominant trait. Diagnostic clinical criteria include: epistaxis, telangiectases in mucocutaneous and gastrointestinal sites, arteriovenous malformations (AVMs) most commonly found in pulmonary, hepatic and cerebral circulations, and familial inheritance. HHT is transmitted in 90% of the cases as an autosomal dominant condition due to mutations in either endoglin (ENG), or activin receptor-like kinase 1 (ACVRL1/ALK1) genes (HHT type 1 and 2, respectively).

METHODS

We have carried out a genetic analysis of four independent Spanish families with HHT clinical criteria, which has permitted the identification of new large deletions in ENG. These mutations were first detected using the MLPA technique and subsequently, the deletion breakpoints were mapped using a customized copy number variation (CNV) microarray. The array was designed to cover the ENG gene and surrounding areas.

RESULTS

All tested families carried large deletions ranging from 3-kb to 100-kb, involving the ENG gene promoter, several ENG exons, and the two downstream genes FGSH and CDK9. Interestingly, common breakpoints coincident with Alu repetitive sequences were found among these families.

CONCLUSIONS

The systematic hybridization of DNA from HHT families, with deletions or duplications, to custom designed microarrays, could allow the mapping of breakpoints, coincident with repetitive Alu sequences that might act as "hot spots" in the development of chromosomal anomalies.

Signet ring cell (mucin producing) adenocarcinoma is a rare low grade salivary gland malignancy. While currently designated as an adenocarcinoma, myoepithelial differentiation has been implied in previously reported cases. We herein perform a survey of our cases of signet ring cell adenocarcinoma and review the literature in order to refine categorization of this rare tumor. Five cases were retrieved. One was reclassified as a mammary analogue secretory carcinoma, leaving four that fulfilled the criteria for signet ring cell adenocarcinoma: the presence of prominent signet ring or vacuolated cells arranged in islands, interconnecting strands, cords or sheets in a myxoid or hyaline stroma, or pools of mucin. An extensive panel of histochemical and immunohistochemical stains and fluorescence in situ hybridization (FISH) (modeled after common phenotypes and molecular alterations seen in signet ring and myoepithelial tumors at other sites) was performed. The male-to-female ratio was 3:1. The mean age was 56 years (range 18-81). Sites involved included buccal mucosa (2), soft palate (1) and deep parotid (1). Perineural and angiolymphatic invasion were present in three and two cases respectively. One patient was lost to follow up and the remainder were alive and without disease at time of last follow up (mean 38 months). All cases showed mucicarmine positive vacuolated/signet ring cells embedded in a myxoid stroma. Three cases showed at least focal p63 staining and two cases showed positivity for calponin. Membranous E-cadherin was retained in all cases. FISH was negative for ETV6, EWSR1, and ALK1 rearrangements in all four cases. Based on the current series and the previously reported cases, it is evident that signet ring adenocarcinomas have a dual secretory and myoepithelial phenotype and thus as a whole more appropriately designated as 'secretory myoepithelial carcinoma.' They behave in a fairly indolent fashion and do not share the major molecular alterations seen in other signet ring and myoepithelial tumor types.

Hereditary hemorrhagic telangiectasia (HHT) is a vascular rare disease characterized by nose and gastrointestinal bleeding, skin and mucosa telangiectasias, and arteriovenous malformations in internal organs. HHT shows an autosomal dominant inheritance and a worldwide prevalence of approximately 1:5000 individuals. In >80% of patients, HHT is caused by mutations in either ENG (HHT1) or ACVRL1 (HHT2) genes, which code for the membrane proteins Endoglin and Activin A Receptor Type II-Like Kinase 1 (ALK1), respectively, both belonging to the TGF-β/BMP signaling pathway. In this work, we describe a novel mutation in exon 9 of ENG (c.1145 G > A) found in five affected members of a family, all of them with characteristic symptoms of HHT. This mutation involves Cys382 residue of the Endoglin protein (p.Cys382 > Tyr) in the zona pellucida (ZP) module of its extracellular region. This is a critical residue involved in a conserved intrachain disulphide bond and in the correct folding of the protein. In fact, transfection studies in human cells using Endoglin expression vectors demonstrated that the p.Cys382 > Tyr mutation results in a marked reduction in the levels of the Endoglin protein. These results demonstrate the pathogenic role for this variant in HHT1 and confirm the key function of Cys382 in Endoglin expression.

Pulmonary arterial hypertension (PAH) is an uncommon disorder that may be hereditable, idiopathic or associated with conditions like drug exposure, connective tissue disease, HIV infection or congenital heart disease. Familial disease are usually due to mutations in the bone morphogenic protein receptor type 2 (BMPR2), activin-like kinase-type 1 (ALK1) and endoglin (ENG). Functional and structural changes in the pulmonary vasculature lead to increased pulmonary vascular resistance. Vascular remodeling involves endothelial dysfunction, activation of fibroblasts and smooth muscle cells and recruitment of circulating progenitor cells. Vasoconstriction has also been shown to affect the remodeling process. Genetics, cellular and molecular basis of PAH are discussed in the paper.

OBJECTIVE

Our study aimed to investigate the relationship between exercise-induced pulmonary arterial hypertension and genetic changes related to the transforming growth factor-β (TGF-β) signalling pathway in patients with cardiac septal defects.

METHODS

In a population-based group of 44 patients (age 13-25 years) with either isolated ventricular septal defect (n=27) or isolated atrial septal defect (n=17), right ventricular systolic pressure response to submaximal exercise was studied by echocardiography and classified as normal (≤45 mmHg), borderline (45-50 mmHg) or abnormal (>50 mmHg). Three genes related to TGF-β, bone morphogenetic protein receptor type 2 (BMPR2), activin receptor-like kinase 1 (ALK1) and endoglin (ENG), were analyzed by DNA sequencing (only BMPR2) and multiplex ligand-dependent probe amplification (BMPR2, ALK1 and ENG).

RESULTS

Pressure response was borderline in five and abnormal in nine patients. Five patients showed mutations in exon 12 of the bone morphogenetic protein receptor type 2 gene. The previously described polymorphism S775N (c. 2324, G>> A) was found in three patients with normal pressure response. The mutation Y589C (c. 1766, A>> G), which has not been described previously, was found in two of 14 patients with borderline/abnormal pressure response.

CONCLUSIONS

Genetic changes in the BMPR2 gene may be overrepresented in patients with cardiac septal defects and exercise-induced pulmonary hypertension.

The intracellular signaling mechanisms through which TGF-β regulates pulmonary development are incompletely understood. Canonical TGF-β signaling involves Smad2/3 phosphorylation, Smad2/3·Smad4 complex formation and nuclear localization, and gene regulation. Here, we show that physiologically relevant TGF-β1 levels also stimulate Smad1/5 phosphorylation, which is typically a mediator of bone morphogenetic protein (BMP) signaling, in mouse pup pulmonary artery smooth muscle cells (mPASMC) and lung fibroblasts and other interstitial lung cell lines. This cross-talk mechanism likely has in vivo relevance because mixed Smad1/5/8·Smad2/3 complexes, which are indicative of TGF-β-stimulated Smad1/5 activation, were detected in the developing mouse lung using a proximity ligation assay. Although mixed Smad complexes have been shown not to transduce nuclear signaling, we determined that TGF-β stimulates nuclear localization of phosphorylated Smad1/5 and induces the expression of prototypical BMP-regulated genes in the mPASMC. Small-molecule kinase inhibitor studies suggested that TGF-β-regulated Smad1/5 phosphorylation in these cells is mediated by TGF-β-type I receptors, not BMP-type I receptors, but possibly the accessory activin-like kinase (ALK1) receptor. Although work by others suggested that ALK1 is expressed exclusively in endothelial cells in the vasculature, we detected ALK1 mRNA and protein expression in mPASMC in vitro and in mouse pup lungs. Moreover, using an antimurine ALK1 antibody and mPASMC, we determined that ALK1 regulates Smad1/5 phosphorylation by TGF-β. Together, these studies characterize an accessory TGF-β-stimulated BMP R-Smad signaling mechanism in interstitial cells of the developing lung. They also indicate the importance of considering alternate Smad pathways in studies directed at determining how TGF-β regulates newborn lung development.

Using quantitative real-time polymerase chain reaction (QRT-PCR), molecular genetic analysis was carried out for endoglin (ENG) and activin A receptor type II-like kinase 1 (ACVRL1/ALK1) gene rearrangements in a group of 45 clinically confirmed hereditary haemorrhagic telangiectasia (HHT) families with negative direct sequencing results. We detected five large novel deletions, four in the ALK1 gene and one in the ENG gene. In two families, the whole ALK1 gene was deleted. One of these two deletions spanned at least 216 kb and included five neighbouring genes (LOC728503, ANKRD33, ACVR1B, GRASP, and NR4A1). The lack of additional symptoms in the patient carrying this large deletion indicates that heterozygous loss of these five genes has no obvious phenotypical effect. To our knowledge, this is the first report on whole ALK1 gene deletions in HHT patients. We rescreened our 45 families for large rearrangements using the multiplex ligation-dependent probe amplification (MLPA) method. No discrepancies between the results of QRT-PCR and MLPA were found. Our present work proves QRT-PCR as a reliable and sensitive method. Thus, our study supports that screening for large rearrangements should be considered to improve the genetic analysis in HHT patients with no apparent mutations in ALK1 and ENG using direct sequencing.

Inflammatory myofibroblastic tumours (IMTs), also known as inflammatory pseudotumours, include a diverse group of lesions characterised by inflammatory cell infiltration and variable fibrotic responses. Their occurrence in the breast is unusual. We present a case of an IMT of the breast in a 46-year-old woman who complained of a breast mass with palpable axillary lymph node. The initial clinical diagnosis was breast cancer, and the patient underwent a conservative excision with apparently negative margins and an axillary lymph node excisional biopsy. A histopathological examination showed the presence of myofibroblastic spindle cells with mixed inflammatory infiltrates, and the pathological diagnosis was IMT. Significantly, the case we present here is unique in showing anaplastic lymphoma kinase 1 (ALK1) overexpression and ALK1 gene amplification in IMT of the breast. Therefore, our case suggests that ALK1 gene amplification in IMT of the breast has important diagnostic and therapeutic implications.

Although the risk of malignant lymphoma in patients with atopic dermatitis (AD) remains controversial, an increased risk of malignant T-cell lymphoma in patients with AD has been reported. Primary cutaneous anaplastic large cell lymphoma (C-ALCL) is a relatively common distinct clinicopathological entity. However, occurrence of C-ALCL in patients with AD has been rarely reported. Herein, we describe the 5(th) reported case of C-ALCL occurring in a patient with AD and review the clinicopathological features. A 30-year-old Japanese male with a long-standing history of AD presented with a gradually enlarged nodular lesion in the right abdominal wall, which had spontaneously regressed without therapy. Two years later, multiple nodular lesions appeared in his trunk, and swelling of multiple lymph nodes was also detected. Histopathological studies demonstrated diffuse proliferation of large-sized lymphocytes with large convoluted nuclei containing conspicuous nucleoli and relatively rich cytoplasm in the skin and lymph node. Immunohistochemically, these lymphocytes were positive for CD30, CD8, and MUM1, and negative for CD3, CD4, and ALK1. Accordingly, a diagnosis of primary C-ALCL was made. The patient died of disease after various courses of chemotherapy. Our clinicopathological review revealed that the prognosis of C-ALCL occurring in patients with AD is poor because two of 5 patients died of disease. Therefore, albeit extremely rare, AD patients with C-ALCL should be monitored closely, and additional clinicopathological studies are needed to clarify the pathogenesis of C-ALCL occurring in patients with AD.

Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome) is a development disorder of the vasculature characterized by telangiectases and arteriovenous malformations in specific locations. Among monogenic disorders, it is one of the most common, though affected individuals are widely underdiagnosed. The most common features of this disorder, nosebleeds, and telangiectases on the lips, hands, and oral mucosa are often quite subtle. Mutations in at least five genes may result in hereditary hemorrhagic telangiectasia, but mutations in two genes (ENG and ACVRL1/ALK1) account for approximately 85% of cases. Optimal management requires understanding the specific clinical patterns of these vascular malformations, especially their locations and timing during life. Therapeutic modulation of angiogenesis may be an effective therapy.

BACKGROUND

No biomarkers exist to predict benefit from antiangiogenic therapy in metastatic colorectal cancer patients. ACVRL1 (activin receptor like-protein 1) encodes for ALK1, a member of the transforming growth factor-β receptor family, which directs pathologic angiogenesis. We examined the intratumoral expression of ACVRL1 and other angiogenesis pathway-related genes to identify molecular markers in the TRIBE study.

METHODS

Of 503 randomized patients, 228 had sufficient tissue for analysis. Formalin-fixed paraffin-embedded specimens were examined for expression of VEGF-A, VEGF-B, VEGF-C, VEGFR1, VEGFR2, ACVRL1, EphB4, and EGFL7 using reverse transcription polymerase chain reaction. A maximal χ2 approach was used to determine the messenger RNA levels associated with progression-free survival (PFS), overall survival (OS), response rate, early tumor shrinkage, and depth of response. Recursive partitioning trees were constructed to identify composite prognostic biomarker profiles. External validation was conducted in silico using the Oncomine database.

RESULTS

High ACVRL1 expression was associated with superior OS in both treatment arms (FOLFOXIRI [5-fluorouracil, leucovorin, oxaliplatin, irinotecan]-bevacizumab, 32.7 vs. 13.5 months, hazard ratio [HR], 0.38, P = .023; FOLFIRI [5-fluorouracil, leucovorin, irinotecan]-bevacizumab, 35.1 vs. 22.0 months, HR, 0.36, P = .006) and prolonged PFS (11.7 vs. 5.9 months, multivariate HR, 0.17; P = .001) for patients receiving FOLFOXIRI-bevacizumab on univariate and multivariate analyses. In recursive partitioning analysis, ACVRL1 was the strongest discriminator of the response rate, PFS, and OS in patients receiving FOLFOXIRI-bevacizumab and of OS in patients receiving FOLFIRI-bevacizumab. In silico validation revealed significant associations between ACVRL1 expression, disease recurrence, and 1-year survival (P < .05) among all colorectal cancer stages.

CONCLUSIONS

ACVRL1 expression could serve as a prognostic biomarker in metastatic colorectal cancer patients receiving chemotherapy and bevacizumab and warrants further evaluation in prospective studies.

BACKGROUND

Peri-implant breast seroma is a late clinical presentation of reconstructive surgery or augmentation mammoplasty with breast implants. Pre-operative cytological evaluation of the peri-implant breast seroma is a common clinical approach, showing mainly an inflammatory reaction or more rarely a breast implant-associated anaplastic large cell lymphoma. Herein, we reported the role of cytology in the evaluation of peri-implant breast seroma and its critical pre-operative implications.

METHODS

Eight cases of peri-implant breast seroma from files at Luigi Vanvitelli University were identified between January and December 2017. In all cases, seroma was aspirated; cytospins were performed and stained by Papanicolaou stain; finally, in all cases, a cell block was obtained for immunocytochemical evaluation and, in one case, for FISH to detect ALK1-gene translocation.

RESULTS

The median age of patients was 48 years and the mean time between the implant placement and the occurrence of peri-implant breast seroma was 18 months. Microscopic examination showed breast implant-associated anaplastic large cell lymphoma in one case, aspecific inflammatory reaction in six cases and silicon-associated reaction in one case.

CONCLUSIONS

Peri-implant breast seroma may be caused by several pathological conditions with different clinical behaviour. A proper cytological approach to peri-implant breast seroma allows a correct differential diagnosis between inflammatory conditions and breast implant-associated anaplastic large cell lymphoma and an appropriate management of the patient.

A new proviral integration site for feline leukemia virus (FeLV), termed flit-1, was identified from feline thymic lymphoma. Among 35 FeLV-related tumors examined, 5 of 25 thymic lymphomas demonstrated proviral insertion within flit-1 locus whereas none of four alimentary and five multicentric lymphomas and one T-lymphoid leukemia examined had rearrangement in this region. Extensive sequence analysis has shown that flit-1, which is noncoding, is conserved on human chromosome 12 and mouse chromosome 15. The human and murine homologs of flit-1 are positioned approximately 30-kb upstream to activin-A receptor type II-like 1 (ACVRL1/ALK1) gene. Expression of ACVRL1 mRNA was examined in two of five lymphomas with flit-1 rearrangement and detected in both of the two whereas normal thymuses and seven lymphoid tumors without flit-1 rearrangement had no detectable expression. Therefore, flit-1 appears to represent a novel FeLV proviral common integration domain that may influence lymphomagenesis as insertional mutagenesis.

Inflammatory myofibroblastic tumor (IMT) is a rare lesion found mostly in children and young adults and originates from the lung, abdominopelvic region, and retroperitoneum. Clinical manifestations of IMT or imaging are nonspecific and diagnosis is based on histopathological and immunohistochemical findings. Minority of all IMTs will metastasize. IMT in the oral cavity is an extreme rarity and this is a first case report of IMT in maxilla causing delayed tooth eruption and multiple cervical root resorption with an 11-year-old child. The IMT reported here was positive for smooth muscle actin, vimentin, and anaplastic lymphoma kinase (ALK1) with immunohistochemistry. Only three IMTs of the jaws have been reported so far and none of them had delayed root eruption and tooth resorption. This unusual case of IMT in a child was also ALK1- positive supporting neoplastic origin of her tumor. The case presented here underscores the importance of histopathological examination of the tissue found in any root resorption especially in the case of multiple resorptions.

Microcystic/reticular schwannoma is a recently described variant of schwannoma with a predilection for the gastrointestinal tract, rarely involving the head/neck region. This is the first reported case involving the submandibular gland. We present a case in a 34 year old man with 4.5 cm submandibular mass. Fine needle aspiration suggested a spindle cell lesion. Frozen section evaluation raised the possibility of mucoepidermoid carcinoma. Resection showed a well circumscribed mass with a mucoid appearance. Histologic findings include a lobular architecture with fibrous septa, a lympho-plasmacytic infiltrate, and scattered lymphoid aggregates at the periphery. There are two distinct histologic patterns with solid areas of spindle cells and areas of spindle/ovoid cells with a microcystic pattern in a myxoid background. The tumor has a pushing border, with extension into adipose and adjacent parenchyma, without cytologic atypia or necrosis. Immunohistochemical stains are positive for S-100 and CD34, and negative for calponin, mammoglobin, ALK1, p63, ER, GFAP, SMA, desmin, cytokeratin 7, cytokeratin AE1/AE3, and C-Kit. Mucicarmine stain is negative. Recognition of this benign unusual variant of schwannoma is paramount for appropriate conservative treatment due to the morphologic and immunohistochemical overlap with primary salivary gland carcinomas.

Osteoarthritis (OA) is a common degenerative joint disease; however, its underlying pathogenesis remains to be elucidated. Previous studies have demonstrated that the transforming growth factor‑β (TGF‑β) signaling pathway has a role in the initiation and development of OA. Additionally, latent TGF‑β‑binding protein‑1 (LTBP‑1) modulates the activity of the TGF‑β‑mothers against decapentaplegic (Smad) signaling pathway in numerous diseases, including malignant glioma. The present study demonstrated that expression of LTBP‑1 is increased in OA synovial tissues compared with normal synovial tissues. The effect of TGF‑β was identified to be mediated by phosphorylated(p)‑(Smad)2/3, which may activate activin‑like kinase (ALK)5 receptor, and by p‑Smad1/5/8, which may induce ALK1, thereby stimulating expression of matrix metalloproteinase‑(MMP)‑13 in OA fibroblast‑like synoviocytes (FLS). Compared with normal FLS, OA FLS demonstrated an increased p‑Smad1/5/8:p‑Smad2 ratio, which led to elevated MMP‑13 expression and aggravation of OA. Furthermore, knockdown of the LTBP‑1 gene by siRNA transfection in OA FLS reduced p‑Smad1/5/8 expression without affecting TGF‑β mRNA levels, although p‑Smad2 expression increased. It was also demonstrated that OA FLS exhibited increased proliferation compared with normal FLS in vitro. Furthermore, siRNA‑mediated downregulation of LTBP‑1 reduced proliferation of OA FLS. In conclusion, the present study demonstrated that an alteration in the p‑Smad1/5/8:p‑Smad2 ratio as well as association between p‑Smad1/5/8 and MMP‑13 expression in human OA FLS, may contribute to the development of OA. The results of the present study suggested that LTBP‑1 is a modulator of the TGF‑β signaling pathway in human OA FLS, which may aid in elucidating the mechanism underlying the pathology of OA.

Transforming growth factor beta 1 (TGF-beta1) modulates male reproductive function. Genetically modified mice overexpressing alpha/beta subunits of hCG (hCG+) show Leydig cell hyperplasia/hypertrophy at prepuberty that disappears as the mice approach adulthood. In this study we analyzed the gene expression of TGF-beta1, its specific receptors, type II (TGF-betaRII) and type I (activin receptor-like kinase 1 and 5: ALK1 and ALK5), and co-receptor endoglin (CD105) in purified Leydig cells from hCG+ and wild-type mice at 3 and 8 weeks of age and the occurrence of TGF-beta1, ALK1 and ALK5 by immunohistochemistry. The expression of TGF-beta1 was higher in hCG+ mice at both ages studied, and no changes were observed in TGF-betaRII. ALK5 diminished with age in wild-type mice, whereas ALK1 decreased in hCG+ mice at 8 weeks of age. Endoglin expression showed a marked increase in 3-week-old hCG+ animals. In vitro incubation of Leydig cells from wild-type animals with hCG (10 IU/ml) increased TGF-beta1 and ALK5 expression. Progesterone (10(-6) M) induced endoglin expression. These studies provide novel evidence for differential gene and protein expression of ALK1 and ALK5 at different ages and endoglin expression and hormonal, in purified Leydig cells.

Inflammatory fibroid polyp (IFP) represents a rare cause of gastrointestinal polypoid disease in childhood. Τhe lesion has been described by various names beyond the currently accepted term, including "Vanek's tumour," eosinophilic or submucosal granuloma, gastric fibroma with eosinophilic infiltration, inflammatory pseudotumor, and hemangiopericytoma. The etiopathogenesis and origin of the mesenchymal spindle-shaped cells that comprise the polyp remains enigmatic. Recent studies have shown familial occurrence, expression of platelet-derived growth factor receptor (PDGFRA) and oncogenic PDGFRA mutations in the majority of lesions, suggestive of a neoplastic nature. We present a rare case of a 10-year-old boy with an IFP of the terminal ileum, who presented acutely with intussusception and was treated with a right hemicolectomy. Postoperative course was uneventful and the patient has been asymptomatic during follow-up. Histopathology and immunohistochemical analysis excluded inflammatory myofibroblastic tumor (negative for Alk1, desmin, smooth muscle actin [SMA]), gastrointerstinal stromal tumors (GIST) (negative for CD117) and schwannoma (negative for S100). The lesion was positive for CD34 and faintly for vimentin. Despite the classification of IFPs as a mesenchymal benign neoplasm, in the vast majority of cases, surgical excision alone was curative, and no reports exist of a malignant transformation. A cautious approach with periodic surveillance of the affected children seems reasonable though.

Transforming growth factor-β (TGF-β) is a multifunctional growth factor involved in many physiological processes including wound healing and inflammation. Excessive TGF-β signaling in the skin has been implicated in fibrotic skin disorders such as keloids and scleroderma. We previously identified CD109 as a TGF-β co-receptor and inhibitor of TGF-β signaling and have shown that transgenic mice overexpressing CD109 in the epidermis display decreased scarring. In certain cell types, in addition to the canonical type I receptor, ALK5, which activates Smad2/3, TGF-β can signal through another type I receptor, ALK1, which activates Smad1/5. Here we demonstrate that ALK1 is expressed and co-localizes with CD109 in mouse keratinocytes and that mice overexpressing CD109 in the epidermis display enhanced ALK1-Smad1/5 signaling but decreased ALK5-Smad2/3 signaling, TGF-β expression, and extracellular matrix production in the skin when compared with wild-type littermates. Furthermore, treatment with conditioned media from isolated keratinocytes or epidermal explants from CD109 transgenic mouse skin leads to a decrease in extracellular matrix production in mouse skin fibroblasts. Taken together, our findings suggest that CD109 differentially regulates TGF-β-induced ALK1-Smad1/5 versus ALK5-Smad2/3 pathways, leading to decreased extracellular matrix production in the skin and that epidermal CD109 expression regulates dermal function through a paracrine mechanism.

BACKGROUND

Patients with platinum-refractory, recurrent or metastatic squamous cell carcinoma of the head and neck (RM-SCCHN) have limited options. Activin receptor-like kinase 1 (ALK1) is a type I receptor of the transforming growth factor β superfamily expressed on activated endothelial cells. Dalantercept is an ALK1 receptor fusion protein that acts as a ligand trap to block signaling through ALK1 and inhibits stages of angiogenesis involved in blood vessel maturation and stabilization. In a phase 1 study, dalantercept demonstrated clinical activity in patients with RM-SCCHN. The objective of the current study was to evaluate the activity of dalantercept in RM-SCCHN.

METHODS

Forty-six patients received dalantercept at doses of 80 mg (n = 2), 0.6 mg/kg (n = 13), or 1.2 mg/kg (n = 31) subcutaneously every 3 weeks. The primary endpoint was the overall response rate according to Response Evaluation Criteria in Solid Tumors (RECIST version 1.1). Secondary endpoints included progression-free survival and overall survival, safety and tolerability, and pharmacokinetic and pharmacodynamic assessments.

RESULTS

Forty patients were evaluable for response (13 who received dalantercept 0.6 mg/kg and 27 who received dalantercept 1.2 mg/kg). The overall response rate was 5% (n = 2), and 35% of patients had stable disease; 44% of patients who received 1.2 mg/kg and 30.8% of those who received 0.6 mg/kg achieved disease control (partial response or stable disease). The median progression-fee survival was 1.4 months (95% confidence interval, 1.3-2.2 months), and the median overall survival was 7.1 months (95% confidence interval, 5.5-11.1 months). Drug-related adverse events (>15%) were anemia, fatigue, peripheral edema, headache, and hyponatremia.

CONCLUSIONS

In an unselected, heavily pretreated population of patients with RM-SCCHN, dalantercept monotherapy resulted in a favorable safety profile but only modest dose-dependent activity, and it did not meet the primary efficacy objective of the study. Cancer 2016;122:3641-9. © 2016 American Cancer Society.

Altered pulmonary angiogenesis contributes to disrupted alveolarization, which is the main characteristic of bronchopulmonary dysplasia (BPD). Transforming growth factor β (TGFβ) plays an important role during lung vascular development, and recent studies have demonstrated that endoglin is engaged in the modulation of TGFβ downstream signalling. Although there are two different isoforms of endoglin, L- and S-endoglin, little is known about the effect of S-endoglin in developing lungs. We analysed the expression of both L- and S-endoglin in the lung vasculature and its contribution to TGFβ-activin-like kinase (ALK)-Smad signalling with respect to BPD development. Hyperoxia impaired pulmonary angiogenesis accompanied by alveolar simplification in neonatal mouse lungs. S-endoglin, phosphorylated Smad2/3 and connective tissue growth factor levels were significantly increased in hyperoxia-exposed mice, while L-endoglin, phosphor-Smad1/5 and platelet-endothelial cell adhesion molecule-1 levels were significantly decreased. Hyperoxia suppressed the tubular growth of human pulmonary microvascular endothelial cells (ECs), and the selective inhibition of ALK5 signalling restored tubular growth. These results indicate that hyperoxia alters the balance in two isoforms of endoglin towards increased S-endoglin and that S-endoglin attenuates TGFβ-ALK1-Smad1/5 signalling but stimulates TGFβ-ALK5-Smad2/3 signalling in pulmonary ECs, which may lead to impaired pulmonary angiogenesis in developing lungs.

Anti-angiogenic therapy represents a very promising approach in cancer treatment, as most tumors needs to be supplied by a functional vascular network in order to grow beyond the local boundaries and metastatize. The accessibility of vessels to drug delivery and the broad spectrum of cancers treatable with the same compound have arisen interest in research of suitable molecules, with several, especially targeting the VEGF pathway, entered in clinical trials and approved by the Food and Drug Administration. Despite good results, the major hurdle resides in the limited duration of an effective clinical response before tumors start to grow again. Thus, researchers are looking for different alternative targets for a combined and parallel multi-targeting of angiogenic signaling circuits. Activin Receptor-like kinase 1 (ALK1) is a TGF-β type I receptor with high affinity for the BMP9 member of Bone Morphogenic Proteins superfamily: it is expressed mainly, even if not exclusively, on endothelial cells and seems to be involved in the regulatory phase of angiogenesis. Despite a non-completely elucidated mechanism, the targeting of this pathway, both by a soluble ALK1-Fc receptor developed by Acceleron Pharma and by a fully human monoclonal antibody developed by Pfizer, has achieved encouraging results. After having briefly summarized the state of the art of anti-angiogenic therapy, we will first review existing evidence about the molecular mechanisms of ALK1 signaling and we will then analyse in detail the pre-clinical and clinical data available about these two drugs.

Some of the limitations of fine needle aspiration (FNA) in the cytodiagnosis of lymphoma include problems encountered in differentiating reactive hyperplasia from low-grade non-Hodgkin lymphoma (NHL), lower cytodiagnostic accuracy for NHL with a follicular (nodular) pattern and nodular sclerosis type of classical Hodgkin lymphoma (HL), and overlapping morphological features between T-cell-rich B-cell lymphoma (TCRBCL), anaplastic large cell lymphoma (ALCL), and HL. Immunocytochemistry may be of help in such situations. The B-cell lymphomas such as small lymphocytic lymphoma/CLL, follicular lymphoma (FL), mantle cell lymphoma (MCL), MALT lymphoma, Burkitt lymphoma (BL), and diffuse large B-cell lymphoma (DLBCL) have pan-B-cell markers (CD19, CD20, CD22, CD23, and CD79a). The FL (centrocytic), MCL, and MALT lymphoma can be differentiated with the use of a panel consisting of CD5, CD10, and CD23. In addition, FL is BCL2+ and MCL is BCL2+ as well as cyclin D1+. The DLBCL is BCL6+ in 60-90% cases. Besides pan B-cell marker, the immunocytochemical profile of BL includes CD10+, BCl6+, EBV±, and Ki67+ (100% cells). TCRBCL, a rare variant of DLBCL can be immunocytochemically differentiated from anaplastic large cell lymphoma (CD45+, CD30+, CD15‒, T±, B‒, EMA+, ALK1±) and classical HL (CD30+, CD15+, CD45‒, B‒, T‒, EMA‒). Unlike classical HL, the nodular lymphocytic predominant HL has a phenotype that includes LCA+, CD20+, CD79a+, CD15‒, and CD30‒. Whereas the immature neoplastic cells of T-lymphoblastic lymphoma (LBL) are CD3+, CD20‒, and Tdt+, the rarely encountered mature T-CLL/T-PLL are immunophenotypically CD3+, CD4+, CD5+, CD7+, CD8‒, CD20‒, CD23‒, and Tdt‒.