NAB2‐STAT6 gene fusion and STAT6 immunoexpression in extrathoracic solitary fibrous tumors: the association between fusion variants and locations

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm harboring NAB2‐STAT6 fusion, which drives STAT6 nuclear relocation. For extrathoracic SFTs, the clinical relevance of this molecular hallmark remains obscure. We assessed STAT6 immunoexpression for 61 extrathoracic SFTs exclusive of the meninges and head and neck, and 25 had analyzable RNAs to distinguish fusion variants by RT–PCR. The immunohistochemical and molecular findings were correlated with clincopathological features and disease‐free survival (DFS). Twenty‐eight males and 33 females had SFTs in the body cavities (n = 31), extremities (n = 17), and trunk (n = 13), categorized into 53 non‐malignant and 8 malignant tumors. The vast majority (n = 57, 93%) exhibited distinctive STAT6 nuclear expression, including malignant ones. The common fusion variants were NAB2ex6‐STAT6ex16/17 in 13 SFTs and NAB2ex4‐STAT6ex2 in 8, while miscellaneous variants were detected only in 4 SFTs in the limbs and trunk but not in any body cavity‐based cases (P = 0.026). The worse DFS was univariately associated with malignant histology (P = 0.04) but unrelated to tumor size, location, or fusion variant. Conclusively, extrathoracic SFTs mostly harbor NAB2ex6‐STAT6ex16/17, followed by NAB2ex4‐STAT6ex2. Miscellaneous variants are significantly rare in SFTs within the body cavities. The clinical aggressiveness of extrathoraic SFTs is associated with malignant histology but unrelated to the NAB2‐STAT6 fusion variants.     

Reduced expression of oestrogen receptor‐β is associated with tumour invasion and metastasis in oestrogen receptor‐α‐negative human papillary thyroid carcinoma

Oestrogens play an important role in the development and progression of papillary thyroid carcinoma (PTC) through oestrogen receptor (ER)‐α and ‐β, which may exert different or even opposing actions in PTC. The roles of ERβ in ERα‐negative PTC are still not clear. This study investigated the expression dynamics of ERβ1 (wild‐type ERβ) and its clinical significance in female ERα‐negative PTC patients. ERβ1 expression was detected in thyroid tissues of 136 female patients diagnosed with PTC. The relationships between ERβ1 expression and clinicopathological/biological factors were also analysed in female ERα‐negative PTC patients. The total score for ERβ1 was significantly lower in female ERα‐negative PTC patients with LNM or ETE when compared to those without LNM or ETE (Z = ?2.923, P = 0.003 and Z = ?3.441, P = 0.001). Accordingly, the total score for ERβ1 was significantly higher in ERα‐negative PTC patients expressing E‐cadherin compared to patients negative for E‐cadherin expression (Z = ?2.636, P = 0.008). The total score was lower in ERα‐negative PTC patients positive for VEGF expression compared to those negative for VEGF expression (Z = ?1.914, P = 0.056). This preliminary study indicates that reduced expression of ERβ1 in female ERα‐negative PTC patients is associated with greater progression of the disease. This may provide insights into the underlying molecular mechanisms of ERβ1 and could help design targeted approaches for treating or even preventing this disease.     

Involvement of α‐ and β‐catenins and E‐cadherin in the development of mammary phyllodes tumours

Tsang J Y S, Mendoza P, Lam C C F, Yu A M C, Putti T C, Karim R Z, Scolyer R A, Lee C S, Tan P H & Tse G M
(2012) Histopathology  61, 667–674 Involvement of α‐ and β‐catenins and E‐cadherin in the development of mammary phyllodes tumours Aims: Phyllodes tumours (PT) are rare but clinically important fibroepithelial tumours of the breast. β‐Catenin, a key component in Wnt signalling, has been shown to be important in the development of PT. It also functions as a component of the cadherin complex, which may therefore be implicated in PT pathogenesis. By assessing stromal α‐catenin, β‐catenin and E‐cadherin expression in 158 PT cases using immunohistochemistry and examining associations with clinicopathological features, we aimed to determine the role of these proteins in PT pathogenesis. Methods and results: Cytoplasmic β‐catenin correlated with α‐catenin expression. A significantly higher expression of both markers was observed in borderline than in benign PT (P = 0.003 and <0.001, respectively), but a lower level was found in malignant PT. Cytoplasmic E‐cadherin expression was significantly higher in borderline and malignant than in benign PT (P = 0.001 and 0.012, respectively), but was not correlated with other markers. Both E‐cadherin and α‐catenin showed stronger correlations with histological parameters than β‐catenin. α‐Catenin showed a significant correlation with recurrence (P = 0.005 and 0.016, respectively). Conclusions: α‐ and β‐catenins may be important in the early stages of PT development, while E‐cadherin may be required for malignant development. The correlation of α‐catenin expression with tumour recurrence may be relevant in predicting PT behaviour.     

Oestrogen receptor‐β1 but not oestrogen receptor‐βcx is of prognostic value in apocrine carcinoma of the breast

Apocrine carcinoma of the breast, which frequently expresses oestrogen receptor‐β (ER‐β) in the absence of ER‐α and only infrequently is treated endocrinologically, gives an opportunity to investigate the clinicopathological role of ER‐β in breast cancer independent of ER‐α expression or tamoxifen treatment. Several isotypes of ER‐β, ER‐β1–5 etc., have been identified thus far; however, the clinicopathological importance of each ER‐β isotype in breast cancer is still uncertain. Here we aimed to clarify the clinicopathological importance of ER‐β1 and ER‐βcx (ER‐β2) in apocrine carcinomas, immunohistochemically examining expressions of ER‐β1 and ER‐βcx in 47 apocrine carcinomas. Positivity for ER‐β1 and ER‐βcx was observed in 41 (87%) and 18 (38%) of 47 cases, respectively. ER‐β1 positivity was related to smaller tumor size (P=0.0359), lower histological grade (P=0.0322), and higher disease‐free survival (P<0.0001), whereas ER‐βcx status was related to none of these parameters. ER‐β1 positivity was also associated with favorable clinical outcome in 24 so‐called triple‐negative (ER‐α‐negative/PR‐negative/HER2‐negative) apocrine carcinomas. ER‐β1 itself, independent of ER‐α expression and tamoxifen treatment, seems to have a tumor‐suppressive effect, at least in apocrine carcinomas. Further study of ER‐β1 is desired to optimize breast cancer treatment.     

Accelerated tumour metastasis due to interferon‐γ receptor‐mediated dissociation of perivascular cells from blood vessels

Angiostasis mediated by interferon (IFN)‐γ is a key mechanism of anti‐tumour immunity; however, the effect of IFN‐γ on host vascular endothelial growth factor A (VEGFA)‐expressing cells during tumour progression is still elusive. Here, we developed transgenic mice with IFN‐γ receptor (IFNγR) expression under control of the Vegfa promoter (V‐γR). In these mice, the IFN‐γ responsiveness of VEGFA‐expressing cells led to dramatic growth suppression of transplanted lung carcinoma cells. Surprisingly, increased mortality and tumour metastasis were observed in the tumour‐bearing V‐γR mice, in comparison with the control wild‐type and IFNγR‐deficient mice. Further study showed that perivascular cells were VEGFA‐expressing cells and potential IFN‐γ targets. In vivo, tumour vascular perfusion and pericyte association with blood vessels were massively disrupted in V‐γR mice. In vitro, IFN‐γ inhibited transforming growth factor‐β signalling by upregulating SMAD7, and therefore downregulated N‐cadherin expression in pericytes. Importantly, IFN‐γ neutralization in vivo with a monoclonal antibody reduced tumour metastasis. Together, the results suggest that IFNγR‐mediated dissociation of perivascular cells from blood vessels contributes to the acceleration of tumour metastasis. Thus, the inhibition of tumour growth via IFN‐γ‐induced angiostasis might also accelerate tumour metastasis. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Novel ASAP1‐USP6, FAT1‐USP6, SAR1A‐USP6, and TNC‐USP6 fusions in primary aneurysmal bone cyst

Aneurysmal bone cyst (ABC) is a benign but locally aggressive neoplasm, with a tendency for local recurrence. In contrast to other bone tumors with secondary cystic change, ABC is characterized by USP6 gene rearrangement. There is a growing list of known USP6 fusion partners, characterization of which has been enabled with the advent of next‐generation sequencing (NGS). The list of known fusion partners includes CDH11, CNBP, COL1A1, CTNNB1, EIF1, FOSL2, OMD, PAFAH1B1, RUNX2, SEC31A, SPARC, STAT3, THRAP3, and USP9X. Using NGS, we analyzed a series of 11 consecutive ABCs and identified USP6 fusions in all cases, providing further evidence that USP6 fusions are universally present in primary ABCs. We identified four novel fusion partners in five ABCs and confirmed them by RT‐PCR and Sanger sequencing, ASAP1, FAT1, SAR1A, and TNC (in two cases). Because of high sensitivity and specificity, detection of a USP6 fusion by NGS may assist in differentiating between ABC and its mimics, especially in small biopsy samples when a definite diagnosis cannot be achieved on morphological grounds alone. Further studies with a large number of cases and follow‐up are needed to determine whether different fusion partners are associated with specific clinical and pathologic features of ABCs.     

β‐Catenin (CTNNB1) mutations and clinicopathological features of mesenteric desmoid‐type fibromatosis

Aims and methods: Desmoid‐type fibromatosis (desmoid) is a fibroblastic tumour that shows locally aggressive growth. Mesenteric desmoid is a rare lesion that shares morphological and biological features with fibromatoses occurring in the abdominal wall or in extraabdominal sites, but differs in terms of gross appearance and clinical presentation. We report on a series of 56 cases of mesenteric desmoids from our consultation files and compare them with cases of non‐mesenteric desmoids and retroperitoneal fibrosis. Results: Primary diagnosis of desmoid‐type fibromatosis was correct in 42%, and gastrointestinal stromal tumour was a common misdiagnosis. Nuclear expression of β‐catenin was detected in 91.6% of all desmoids. Mutational analysis of exon 3 of the β‐catenin gene (CTNNB1) revealed that mesenteric desmoids carried mutations significantly more often (51/56, 91.1%) than non‐mesenteric tumours (20/28; 71.4%; P = 0.027). p.T41A occurred significantly more frequently in mesenteric fibromatoses (80.4%) than in abdominal wall and extra‐abdominal fibromatoses (46.4%; P = 0.002). Two novel mutations (p.S45C and p.D32G) were found. In retroperitoneal fibrosis, mutations and nuclear β‐catenin expression were absent. β‐Catenin‐negative desmoids either carried a CTNNB1 mutation or were associated with Gardner syndrome. Conclusions:  Our study provides evidence that some clinical and genetic features of mesenteric desmoids differ from those of non‐mesenteric fibromatosis, and corroborates the usefulness of mutational analysis, especially in diagnosing β‐catenin‐negative mesenteric desmoids.     

Changes in calsequestrin,TNF‐α, TGF‐β and MyoD levels during the progression of skeletal muscle dystrophy in mdx mice: a comparative analysis of the quadriceps,diaphragm and intrinsic laryngeal muscles

In Duchenne muscular dystrophy (DMD), the search for new biomarkers to follow the evolution of the disease is of fundamental importance in the light of the evolving gene and pharmacological therapies. In addition to the lack of dystrophin, secondary events including changes in calcium levels, inflammation and fibrosis greatly contribute to DMD progression and the molecules involved in these events may represent potential biomarkers. In this study, we performed a comparative evaluation of the progression of dystrophy within muscles that are differently affected by dystrophy (diaphragm; DIA and quadriceps; QDR) or spared (intrinsic laryngeal muscles) using the mdx mice model of DMD. We assessed muscle levels of calsequestrin (calcium‐related protein), tumour necrosis factor (TNF‐α; pro‐inflammatory cytokine), tumour growth factor (TGF‐β; pro‐fibrotic factor) and MyoD (muscle proliferation) vs. histopathology at early (1 and 4 months of age) and late (9 months of age) stages of dystrophy. Fibrosis was the primary feature in the DIA of mdx mice (9 months: 32% fibrosis), which was greater than in the QDR (9 months: 0.6% fibrosis). Muscle regeneration was the primary feature in the QDR (9 months: 90% of centrally nucleated fibres areas vs. 33% in the DIA). The QDR expressed higher levels of calsequestrin than the DIA. Laryngeal muscles showed normal levels of TNF‐α, TGF‐β and MyoD. A positive correlation between histopathology and cytokine levels was observed only in the diaphragm, suggesting that TNF‐α and TGF‐β serve as markers of dystrophy primarily for the diaphragm.     

β‐Catenin and E‐cadherin expression in stage I adult‐type granulosa cell tumour of the ovary: correlation with tumour morphology and clinical outcome

Aims: To study E‐cadherin and β‐catenin expression in stage I adult‐type granulosa cell tumours (AGCTs) and correlate the findings with tumour morphology and clinical outcome. Methods and results: The study group comprised 62 FIGO stage I AGCTs, including 48 stage IA and 14 stage IC cases. Fifty patients (80.6%) had negative clinical follow‐up over periods from 3.0 to 19.2 years (median 6.4 years), and 12 patients (19.4%) developed metastases at intervals of 3.6–16.2 years (median 8.6 years). β‐Catenin and E‐cadherin were expressed in 62 (100%) and 53 (85%) primary tumours, respectively, and staining was more consistent and intense in areas showing sex cord‐like morphology. In contrast, diffuse tumour areas often showed weak or moderate staining (β‐catenin) or were negative (E‐cadherin), and there was reduced expression of both proteins in luteinized cells. Reduced β‐catenin expression in primary tumours correlated with increased risk of recurrence (P = 0.002) and a shorter time interval to recurrence, whereas there was no correlation between E‐cadherin staining and the risk of metastases. Conclusions: Localized variations in adhesion protein expression may partly explain the diverse morphological patterns exhibited by AGCT, and reduced β‐catenin staining in primary tumours may have value as an adverse prognostic factor.     

Submandibular gland morphogenesis: Stage‐specific expression of TGF‐α/EGF,IGF, TGF‐β, TNF,and IL‐6 signal transduction in normal embryonic mice and the phenotypic effects of TGF‐β2, TGF‐β3, and EGF‐r null mutations

Branching morphogenesis of the mouse submandibular gland (SMG) is dependent on cell‐cell conversations between and within epithelium and mesenchyme. Such conversations are typically mediated in other branching organs (lung, mammary glands, etc.) by hormones, growth factors, cytokines, and the like in such a way as to translate endocrine, autocrine, and paracrine signals into specific gene responses regulating cell division, apoptosis, and histodifferentiation. We report here the protein expression in embryonic SMGs of four signal transduction pathways: TGF‐α/EGF/EGF‐R; IGF‐II/IGF‐IR/IGF‐IIR; TGF‐βs and cognate receptors; TNF, IL‐6, and cognate receptors. Their in vivo spatiotemporal expression is correlated with specific stages of progressive SMG development and particular patterns of cell proliferation, apoptosis, and mucin expression. Functional necessity regarding several of these pathways was assessed in mice with relevant null mutations (TGF‐β2, TGF‐β₃, EGF‐R). Among many observations, the following seem of particular importance: (1) TGF‐α and EGF‐R, but not EGF, are found in the Initial and Pseudoglandular Stages of SMG development; (2) ductal and presumptive acini lumena formation was associated with apoptosis and TNF/TNF‐R1 signalling; (3) TGF‐β2 and TGF‐β3 null mice have normal SMG phenotypes, suggesting the presence of other pathways of mitostasis; (4) EGF‐R null mice displayed an abnormal SMG phenotype consisting of decreased branching. These and other findings provide insight into the design of future functional studies. Anat Rec 256:252–268, 1999. © 1999 Wiley‐Liss, Inc.     

Stromal CD10 expression and relationship to the E‐cadherin/β‐catenin complex in breast carcinoma

Kim H‐S, Kim G Y, Kim Y W, Park Y‐K, Song J‐Y & Lim S‐J
(2010) Histopathology 56, 708–719
Stromal CD10 expression and relationship to the E‐cadherin/β‐catenin complex in breast carcinoma Aims: Previous investigations have indicated that stromal CD10 expression, and altered levels of both E‐cadherin and β‐catenin, are associated with the biological aggressiveness of human carcinoma. The aim was to evaluate stromal CD10 expression and the association of stromal CD10 with E‐cadherin and β‐catenin in breast carcinoma. Methods and results: The expression of CD10, E‐cadherin and β‐catenin was immunohistochemically analysed in tissue microarrays containing 104 cases of invasive ductal carcinoma (IDC) and 10 cases of ductal carcinoma in situ (DCIS). Stromal CD10 was detected in 49.5% (50/101) of the IDC. No immunoreactivity was identified in the stromal cells of normal breast, DCIS or intraductal components of IDC. Accumulation of the cytoplasmic β‐catenin was found in 87.0% (87/100) of the IDC. Stromal CD10 expression in IDC was significantly correlated with tumour size (P = 0.027), stage (P < 0.001) and histological grade (P = 0.006), the presence of nodal (P = 0.048) and distant (P = 0.015) metastases, oestrogen receptor‐negative status (P = 0.016), cytoplasmic β‐catenin accumulation (P = 0.031) and lower overall survival rate (P = 0.041). Conclusions: Stromal CD10 expression in IDC may constitute an important prognostic marker. Stromal CD10 expression with associated aggressive features might be related to aberrant β‐catenin expression.