Infrequent loss of SMARCA4, SMARCA2, and SMARCB1 expression in uterine mesenchymal tumors.

SMARCA4-deficient uterine sarcoma (SMARCA4-DUS) was recently proposed as a new entity of uterine sarcoma. Reported cases of SMARCA4-DUS showed the loss of SMARCA4 and SMARCA2 expression. However, the prevalence of their deficiency in uterine mesenchymal tumors remains unclear. This study immunohistochemically examined the expression of SMARCA4, SMARCA2, and SMARCB1 in 206 uterine mesenchymal tumors and detected a round cell tumor with the loss of SMARCA4 and SMARCA2 and a low-grade endometrial stromal sarcoma with SMARCA4 deficiency. The remaining 204 cases, including 170 smooth muscle tumors, 22 endometrial stomal nodule/sarcomas, seven undifferentiated uterine sarcomas, two adenosarcomas, one uterine tumor resembling ovarian sex cord tumor, and two perivascular epithelioid cell tumors, retained the expression of both SMARCA4 and SMARCA2. All tumors retained SMARCB1 expression. The round cell tumor with the loss of SMARCA4 and SMARCA2 was composed of diffuse small round cell growth with follicle-like spaces, which resembled small cell carcinoma of the ovary, hypercalcemic type. Immunohistochemically, the tumor showed the proficient expression of mismatch repair proteins and wild-type p53 expression, which favored SMARCA4-DUS; however, the tumor harbored the PIK3CA mutation, and thus, was reclassified as undifferentiated endometrial carcinoma. In conclusion, SMARCA4, SMARCA2, and SMARCB1 were rarely deficient in uterine mesenchymal tumors. SMARCA4 immunohistochemistry has potential in the diagnosis of SMARCA4-DUS with the exclusion of some tumors showing its deficiency, such as endometrial stromal sarcoma and undifferentiated carcinoma. Undifferentiated carcinoma may show an indistinguishable morphology and immunophenotype from SMARCA4-DUS, and thus, molecular analysis is required for their distinction in diagnostic practice.

Loss of SMARCB1 expression in colon carcinoma.

SMARCB1 is a tumor suppressor gene, which is part of SWI/SNF complex involved in transcriptional regulation. Recently, loss of SMARCB1 expression has been reported in gastrointestinal carcinomas. Our purpose was to evaluate the incidence and prognostic value of SMARCB1 loss in colon carcinoma (CC). Patients with stage III CC (n= 1695), and a second cohort of 23 patients with poorly differentiated CC were analyzed. Immunohistochemistry for SMARCB1 was performed on tissue microarrays, and cases with loss of expression were controlled on whole sections. Loss of SMARCB1 was compared with the clinico-pathological and molecular characteristics, and the prognostic value was evaluated. Loss of SMARCB1 was identified in 12 of 1695 (0.7%) patients with stage III CC. Whole section controls showed a complete loss in only one of these cases, corresponding to a medullary carcinoma. SMARCB1 loss was not associated with histological grade, tumor size nor survival. In the cohort of poorly differentiated CC, we detected 2/23 (8.7%) cases with loss of SMARCB1; one was rhabdoid while the other had medullary and mucinous histology. These 2 cases were deficient for MisMatched Repair (dMMR) and mutated for BRAF. SMARCB1 loss is rare in stage III CC, but appears more frequent in poorly differentiated CC.

The Rare Phenomenon of Loss of INI1 Expression at Recurrence/Progression of Primary Central Nervous System Tumors: Report of 3 Cases.

It is extremely rare for loss of immunohistochemical expression of INI1 to occur primarily at recurrence/progression with retained expression at the primary/initial presentation of central nervous system (CNS) tumor. In this article, we present 3 such cases showing loss of INI1 expression primarily at recurrence. All patients were males, aged 7 years (case 1), 11 years (case 2), and 35 years (case 3), diagnosed with low-grade glial/glioneuronal tumor, not otherwise specified (case 1), craniopharyngioma (case 2), and glioblastoma (case 3); all showed retained INI1 protein expression. Case 1 at 12 months recurrence showed a high-grade tumor with relative undifferentiated morphology, case 2 after 104 months showed a sarcomatous progression, and case 3 recurred after 4 months with the presence of relative undifferentiated round cells. All these recurrences showed loss of INI1 expression. Loss of SMARCB1/INI1 gene function resulting in complete loss of INI1 protein expression is not a well-accepted genetic mechanism for transformation/progression as this series emphasizes.

Histone deacetylase inhibitors induce complex host responses that contribute to differential potencies of these compounds in HIV reactivation.

Histone deacetylase (HDAC) inhibitors (HDACis) have been widely tested in clinical trials for their ability to reverse HIV latency but have yielded only limited success. One HDACi, suberoylanilide hydroxamic acid (SAHA), exhibits off-target effects on host gene expression predicted to interfere with induction of HIV transcription. Romidepsin (RMD) has higher potency and specificity for class I HDACs implicated in maintaining HIV provirus in the latent state. More robust HIV reactivation has indeed been achieved with RMD use ex vivo than with SAHA; however, reduction of viral reservoir size has not been observed in clinical trials. Therefore, using RNA-Seq, we sought to compare the effects of SAHA and RMD on gene expression in primary CD4+ T cells. Among the genes whose expression was modulated by both HDACi agents, we identified genes previously implicated in HIV latency. Two genes, SMARCB1 and PARP1, whose modulation by SAHA and RMD is predicted to inhibit HIV reactivation, were evaluated in the major maturation subsets of CD4+ T cells and were consistently either up- or down-regulated by both HDACi compounds. Our results indicate that despite having different potencies and HDAC specificities, SAHA and RMD modulate an overlapping set of genes, implicated in HIV latency regulation. Some of these genes merit exploration as additional targets to improve the therapeutic outcomes of "shock and kill" strategies. The overall complexity of HDACi-induced responses among host genes with predicted stimulatory or inhibitory effects on HIV expression likely contributes to differential HDACi potencies and dictates the outcome of HIV reactivation.

SMARCB1 (INI1)-deficient sinonasal carcinoma: a series of 13 cases with assessment of histologic patterns.

A significant proportion of sinonasal malignancies comprise poorly differentiated/undifferentiated carcinomas that defy accurate histologic classification and behave aggressively. Recent years have seen a refinement of this spectrum by inclusion of novel entities harboring specific genetic alterations, including SMARCB1 (INI1)-deficient sinonasal carcinoma (SDSC), characterized by inactivating alterations in SMARCB1 gene, as demonstrated by loss of INI1 immunoexpression. Cyclin D1 is a cell-cycle regulatory protein downstream of INI1. Loss of INI1 leads to derepression of cyclin D1 transcription, suggesting its role as a putative therapeutic target. However, cyclin D1 expression has not been assessed in SDSCs. We retrieved all sinonasal carcinomas, including sinonasal undifferentiated carcinoma, undifferentiated carcinoma, poorly differentiated squamous cell carcinoma, and adenocarcinoma. Histopathologic features were reviewed. INI1 immunohistochemistry was performed. Cyclin D1 was performed in cases showing INI1 loss. Loss of INI1 staining was seen in 13 cases (5.8%), including 11 males and 2 females (age range, 11-65 years). Original diagnoses included SDSC (3/13), sinonasal undifferentiated carcinoma (3/13), adenocarcinoma (3/13), poorly differentiated squamous cell carcinoma (2/13), and poorly differentiated carcinoma (2/13). Tumors were predominantly basaloid in 6 cases and plasmacytoid/rhabdoid in 5 cases. We identified 2 cases having oncocytoid cells arranged in a gland-like pattern. Significant cyclin D1 immunoexpression was absent. SDSC is a rare, emerging entity that resembles a poorly differentiated carcinoma. Histomorphologic spectrum of these tumors is evolving. In addition to basaloid and plasmacytoid/rhabdoid cells, oncocytoid/adenocarcinoma-like pattern can also be seen in SDSC and predicts INI1 loss. These histologic patterns can further be subjected to INI1 immunohistochemistry for correct diagnosis.

Poorly Differentiated Chordomas Showing Loss of INI1/SMARCB1: A Report of 2 Rare Cases With Diagnostic Implications.

Poorly differentiated chordomas are rare musculoskeletal tumors. Case 1. A 42-year-old lady presented with quadriparesis of 2 months' duration. Radiologic imaging disclosed a soft tissue mass in her left prevertebral- and paravertebral cervical region. Case 2. A 4-year-old male child presented with neck pain and restricted head movements of 1-year duration. Radiologic imaging revealed a contrast enhancing, paraspinal soft tissue mass in his cervical region. Microscopic examination in both the cases revealed a cellular malignant tumor composed of moderate to markedly pleomorphic cells with interspersed mitotic figures, along with focal myxoid change and necrosis. By immunohistochemistry, tumor cells in both cases were diffusely positive for pan cytokeratin (AE1/AE3) and brachyury, whereas these were negative for INI1/SMARCB1. Tumor cells in the second case were also positive for glypican3. The first case developed pulmonary metastasis, while the second case developed recurrence. Poorly differentiated chordomas are uncommon tumors, invariably characterized by loss of INI1. These tumors can be rarely seen in adults and need to be differentiated from their diagnostic mimics, in view of treatment implications and their relatively aggressive clinical outcomes.

Sinonasal SMARCB1 (INI1) Deficient Carcinoma With Yolk Sac Tumor Differentiation: Report of a Case and Comparison With INI1 Expression in Gonadal Germ Cell Tumors.

SMARCB1 (INI1) deficient sinonasal carcinoma is a recently recognized entity with wide histomorphologic spectrum. We present a case of this carcinoma that contained, in addition to a "common" morphology, scattered foci of yolk sac tumor differentiation. The tumor occurred in paranasal sinuses in a 44-year-old woman. Immunohistochemically, it was diffusely negative for INI1, whereas an expression of yolk sac tumor markers (α-fetoprotein, glypican-3, CDX2) was limited to the yolk sac tumor component. For comparison with the present case, we performed INI1 immunostaining on a series of 11 gonadal germ cell tumors with yolk sac tumor differentiation. All of these cases showed strong and diffuse expression of INI1, in contrast with the present sinonasal tumor. Our findings expand the morphologic spectrum of SMARCB1 (INI1) deficient sinonasal carcinoma. In addition, we show preliminarily that gonadal germ cell tumors with yolk sac tumor differentiation are not SMARCB1/INI1-deficient.

INI Expressing Epithelioid Sarcoma with Osteoclastic Giant Cells in a Child: A Case Report with Summary of Prior Published Cases.

BACKGROUND: Epithelioid sarcoma is a heterogeneous tumor with 2 subtypes, classic and proximal. The proximal variant is more aggressive and occurs in proximal location in young adults. CASE REPORT: We present a proximal epithelioid sarcoma in the leg of an 8 year old girl with rhabdoid morphology and scattered osteoclastic giant cells. Nuclear INI-1 was retained. Despite wide local excision, local recurrence occurred at 8 months. Following re-excision, she developed a chest wall metastasis after 9 months. CONCLUSION: Epithelioid sarcoma, proximal type with osteoclastic giant cells in the pediatric age group has not been reported previously and should be considered in the differential diagnoses of tumors with epithelioid cell morphology and scattered osteoclastic giant cells. Retained INI expression helped to differentiate this tumor from malignant rhabdoid tumor.

A mosaic pattern of INI1/SMARCB1 protein expression distinguishes Schwannomatosis and NF2-associated peripheral schwannomas from solitary peripheral schwannomas and NF2-associated vestibular schwannomas.

BACKGROUND: The INI1/SMARCB1 gene protein product has been implicated in the direct pathogenesis of schwannomas from patients with one form of schwannomatosis [SWNTS1; MIM # 162091] showing a mosaic pattern of loss of protein expression by immunohistochemistry [93% in familial vs. 55% in sporadic cases]. AIM OF STUDY: To verify whether such INI1/SMARCB1 mosaic pattern could be extended to all schwannomas arising in the sporadic and familial schwannomatoses [i.e. to SMARCB1-related (SWNTS1) or LZTR1-related (SWNTS2) schwannomatosis or to SMARCB1/LZTR1-negative schwannomatosis] and whether it could be involved in classical NF2 or solitary peripheral schwannomas METHODS: We blindly analysed schwannoma samples obtained from a total of 22 patients including (a) 2 patients (2 males; aged 38 and 55 years) affected by non-familial SMARCB1-associated schwannomatosis (SWTNS1); (b) 1 patient (1 female; aged 33 years) affected by familial schwannomatosis (SWTNS1/ SMARCB1 germ line mutations); (c) 5 patients (3 males, 2 females; aged 33 to 35 years) affected by non-familial (sporadic) LZTR1-associated schwannomatosis (SWNTS2); (d) 3 patients (3 males; aged 35 to 47 years) affected by familial schwannomatosis (SWTNS2/ LZTR1 germ line mutations); (e) 2 patients (1 male, 1 female; aged 63 and 49 years, respectively) affected by non-familial schwannomatosis (SWTNS, negative for SMARCB1, LZTR1 and NF2 gene mutations); (f) 4 patients (3 males, 1 females; aged 15 to 24 years) affected by classical NF2 (NF2: harbouring NF2 germ line mutations; and (g) 5 patients (3 males, 2 females; aged 33 to 68 years) who had solitary schwannomas. [follow-up = 15-30 years; negative for constitutional/somatic mutation analysis for the SMARCB1, LZTR1 and NF2 genes] were (blindly) analyzed. The INI1/SMARCB1 immunostaining pattern was regarded as (1) diffuse positive nuclear staining [= retained expression] or (2) mosaic pattern [mixed positive/negative nuclei = loss of expression in a subset of tumour cells]. RESULTS: All solitary peripheral schwannomas and NF2-associated vestibular schwannomas showed diffuse nuclear INI1/SMARCB1 staining in 97-100% of neoplastic cells; schwannomas obtained from all cases of non-familial and familial schwannomatosis and NF2-associated non-vestibular schwannomas showed a mosaic pattern ranging from 10 to 70% of INI1/SMARCB1-positive expression. We did not record a complete lack of nuclear staining. CONCLUSIONS: The present data suggests that (a) mosaic loss of immunohistochemical INI1/SMARCB1 expression, despite the interlesional variability, is a reliable marker of schwannomatosis regardless of the involved gene and it might help in the differential diagnosis of schwannomatosis vs. solitary schwannomas and (b) INI1/SMARCB1 expression is not useful in the differential with mosaic NF2, since NF2-associated peripheral schwannomas show the same immunohistochemical pattern.

EWSR1-fusion-negative, SMARCB1-deficient primary pulmonary myxoid sarcoma.

Primary pulmonary myxoid sarcoma (PPMS) is a recently defined rare neoplasm with histological and molecular similarity to extraskeletal myxoid chondrosarcoma. To date, 20 cases have been reported. A 48-year-old man presented with a huge mass filling the right hemithorax and extending into the tracheobronchial system. Histological findings were consistent with PPMS. Immunohistochemistry was positive for vimentin, CD10, and EMA, but other lineage-specific markers were negative. SMARCB1 (INI1) expression was lost in the tumour cells. FISH analysis (EWSR1, FUS, NR4A3, and SMARCB1) revealed no abnormalities. This case suggests SMARCB1 loss as a possible alternative molecular event driving EWSR1-negative PPMS.

INI1 (SMARCB1)-Deficient Sinonasal Carcinoma: A Clinicopathologic Report of 2 Cases.

Poorly differentiated sinonasal malignancies are amongst the hardest differential diagnoses in pathology, owing to the large number of rare entities that arise there. Complicating the matter is that most pathologists, including those with experience in head and neck pathology, have little experience in any one of these rare entities. Most patients with sinonasal carcinoma present with locally advanced disease and in the past a combination of chemotherapy, radiotherapy, and surgery would usually be recommended without the specific disease subtype playing a large part of the decision making. However, in the era of "precision medicine" and targeted therapies, the specific tumour subtype and an accurate diagnosis will become increasingly important even for the so-called "undifferentiated carcinoma". Specific entities that tend to enter into the differential diagnosis include olfactory neuroblastoma, sinonasal undifferentiated carcinoma (SNUC), and non-keratinizing squamous cell carcinoma (viral and non-viral). However, recent new entities, such as NUT-midline carcinoma also have to be considered. Recently it was found that a subset of tumours originally diagnosed as one of the aforementioned entities all demonstrated loss of the ubiquitously expressed protein Integrase Interactor 1 (INI1; SMARCB1). These tumours were often basaloid with at least partial rhabdoid differentiation and most were considered a part of the SNUC spectrum. In this report, we describe two additional cases of INI1-deficient sinonasal carcinoma prospectively identified, both of which appeared to have a marked response to neo-adjuvant chemoradiation, a finding not previously described.

Loss of expression of SMARCA4 (BRG1), SMARCA2 (BRM) and SMARCB1 (INI1) in undifferentiated carcinoma of the endometrium is not uncommon and is not always associated with rhabdoid morphology.

AIM: Abnormalities of SMARCB1 (INI1), which encodes a member of the SWI/SNF pathway, are found in neoplasms with rhabdoid morphology, such as malignant rhabdoid tumour of the kidney and atypical teratoid/rhabdoid tumour of the central nervous system. SMARCA4 (BRG1), which encodes another member of the SWI/SNF pathway, and which is mutated in almost all small-cell carcinomas of the ovary, hypercalcaemic type, has been investigated in endometrial carcinomas, and mutations with resultant loss of immunohistochemical staining have been demonstrated in some endometrial undifferentiated carcinomas/dedifferentiated carcinomas. The aim of this study was to evaluate immunohistochemical expression of SMARCA4, SMARCB1 and SMARCA2 in a cohort of undifferentiated endometrial carcinomas, and to correlate expression of these markers with rhabdoid morphology and clinical outcome. METHODS AND RESULTS: Forty undifferentiated endometrial carcinomas (18 pure and 22 dedifferentiated carcinomas) were stained with SMARCA4 (n = 40), SMARCB1 (n = 27), and SMARCA2 (n = 37). SMARCA4 expression was intact in 26 of 40 (65%) cases, lost in 13 of 40 (32.5%) cases, and unassessable in one case (2.5%). SMARCB1 expression was intact in 26 of 27 (96%) cases and lost in one of 27 (4%) cases. SMARCA2 expression was intact in 23 of 37 (62%) cases, lost in 10 of 37 (27%) cases, and unassessable in four cases. SMARCA2 expression showed corresponding loss in nine of the 13 (69%) SMARCA4-deficient cases. Rhabdoid morphology was present in three of 13 (23%) SMARCA4-deficient cases, in two of 10 (20%) SMARCA2-deficient cases, in four of 26 (15%) SMARCA4-intact cases, and in four of 23 (17%) SMARCA2-intact cases. There was no correlation between SMARCA4 or SMARCA2 expression and clinical outcome. CONCLUSIONS: Our study demonstrated that almost one-third of endometrial undifferentiated carcinomas show loss of SMARCA4 and SMARCA2 expression, and that a subset show rhabdoid morphology. The majority of the SMARCA4-deficient cases show concomitant loss of SMARCA2 expression. There is no correlation between SMARCA4 or SMARCA2 expression and outcome. Our results confirm that the SWI/SNF chromatin-remodelling complex is involved in the pathogenesis of endometrial undifferentiated carcinomas.

Atypical teratoid/rhabdoid tumours: clinicopathological characteristics, prognostic factors and outcomes of 22 children from 2010 to 2015 in China.

Atypical teratoid/rhabdoid tumours (AT/RTs) are rare, highly malignant tumours of the central nervous system (CNS) with poor prognosis that usually affect young children. The aim of this study was to assess the clinicopathological features and prognostic factors of AT/RTs. Here, we describe the clinicopathological and immunohistochemical characteristics, along with the treatments and outcomes, of 22 patients with AT/RTs treated in our hospital from 2010 to 2015. Morphologically, cytoplasmic vacuoles, the most common characteristic in our cases, were observed in 68% of the cases. Similarly, vesicular nuclei were detected in 68% of the cases. However, rhabdoid cells were found in only 59.1% of the cases and were not observed in 40.9% of the cases. Immunohistochemical analysis revealed loss of nuclear INI1 expression in all 22 cases. Age, surgical resection and adjuvant therapy, but not tumour location, were associated with AT/RTs patient prognosis. Our results showed that cells with cytoplasmic vacuoles or with vesicular nuclei are more common than rhabdoid cells in patients with AT/RTs and that a lack of INI1 protein expression is the most useful marker for the differential diagnosis of AT/RTs. Young age is a negative prognostic factor, whereas gross total surgical resection and adjuvant therapy are positive prognostic factors for AT/RT patients.

Preclinical Evaluation of Combined Targeted Approaches in Malignant Rhabdoid Tumors.

BACKGROUND/AIM: Rhabdoid tumors (RT) are aggressive pediatric tumors, which show poor prognosis despite use of multimodal intensive therapy. In these tumors, several different oncogenic pathways and epigenetic regulators (like CDK4/6-cyclinD-Rb-signaling, EZH2, histone deacetylases) are contemporaneously deregulated as a consequence of biallelic SMARCB1/SNF5/INI1 alterations. Since these tumors are highly resistant to current therapies, alternative treatment strategies are urgently required. MATERIALS AND METHODS: In this study, we evaluated cytotoxic effects (by MTT tests) of small molecular compounds, which specifically target these deregulated pathways, using either single-drug or combined approaches. Half-maximal inhibitory concentration (IC50) and combined index (CI) were calculated. RESULTS: All target-directed inhibitors blocked cell growth of three different rhabdoid tumor cell lines in vitro. Several combinations of those target-specific drugs synergistically inhibited cell proliferation of rhabdoid tumors. CONCLUSION: Supporting earlier reports, combined target-directed approaches are a promising tool for the therapy of malignant rhabdoid tumors.

Reclassification of rhabdoid tumor and pediatric undifferentiated/unclassified sarcoma with complete loss of SMARCB1/INI1 protein expression: three subtypes of rhabdoid tumor according to their histological features.

Rhabdoid tumor is characterized by rhabdoid cells and shows complete loss of SMARCB1/INI1 protein expression. In existing classifications, the diagnostic synonyms vary depending on the anatomic site: rhabdoid tumors in the central nervous system or extra-central nervous system are, respectively, classified as atypical teratoid/rhabdoid tumor or malignant rhabdoid tumor. In this study, we analyzed the histological, immunohistochemical, microRNA, and clinicopathological statuses of tumors initially diagnosed as malignant rhabdoid tumor (n=33), atypical teratoid/rhabdoid tumor (n=11), and pediatric undifferentiated/unclassified sarcoma (n=8) with complete loss of SMARCB1/INI1 expression, and considered the possibility of their histological reclassification. Our analysis indicated that the tumors could be histologically reclassified into three groups: conventional-type tumors resembling malignant rhabdoid tumor, atypical teratoid/rhabdoid-type tumors resembling atypical teratoid/rhabdoid tumor, and small cell-type tumors resembling malignant lymphoma. The reclassified conventional type was composed of 27 malignant rhabdoid tumors and 9 atypical teratoid/rhabdoid tumors (36 cases). The atypical teratoid/rhabdoid type consisted of six malignant rhabdoid tumors, two atypical teratoid/rhabdoid tumors, and two undifferentiated/unclassified sarcomas (10 cases). The six cases of small cell type were made up of six undifferentiated/unclassified sarcomas. All of the available tumor specimens were positive for vimentin and epithelial marker (EMA, CAM5.2, or AE1/AE3). MicroRNA profiles were not significantly different between the conventional- and small cell-type tumors (Pearson's correlation coefficient: 0.888300 or 0.891388). There was no significant difference in overall survival between atypical teratoid/rhabdoid tumor and malignant rhabdoid tumor (P=0.16). In addition, there were no significant differences in survival between any of the reclassified combinations. In conclusion, we could classify eight tumors initially diagnosed as undifferentiated/unclassified sarcomas into two cases of atypical teratoid/rhabdoid type and six cases of small cell type. We suggest that reclassification of malignant rhabdoid tumors into three groups according to their histologic features rather than the traditional classification by sites of origin would be favorable for their histopathological diagnosis.

Epigenetic regulation of SMARCB1 By miR-206, -381 and -671-5p is evident in a variety of SMARCB1 immunonegative soft tissue sarcomas, while miR-765 appears specific for epithelioid sarcoma. A miRNA study of 223 soft tissue sarcomas.

Complete/partial loss of SMARCB1 nuclear-immunopositivity is characteristic of a certain subset of soft tissue sarcomas (STSs). Our previous work showed that oncomiRs-206,-381, and 671-5p could silence the SMARCB1 mRNA and protein expression and that they display significant overexpression in epithelioid sarcomas (ESs). MiR-765 was overexpressed too, but functionally was inactive in the silencing. In the current work, using quantitative PCR, we conducted a miRNA study of 51 ESs, 20 rhabdoid tumors (RTs), 20 synovial sarcomas (SSs), 15 malignant peripheral nerve sheath tumors (MPNSTs), 11 myoepithelial carcinomas (MECs), and 10 extraskeletal myxoid chondrosarcomas (EMCSs) with complete/partial loss of SMARCB1 nuclear immunostain, in contrast to controls (SMARCB1-immunopositive) of 96 STSs, 13 melanomas and 10 sarcomatoid carcinomas. The SMARCB1 genetic status of ESs was determined by MLPA and FISH. A subset of ESs (5/51) showed biallelic deletion of SMARCB1 with no overexpression of any miRNA, suggesting these tumors could be the counterpart of pediatric RT, at least genetically. Another subset (5/51) was genetically either intact or monoallelic deleted with at least threefold overexpression of one of miR-206,-381,-671-5p, suggesting epigenetic regulation only. 39/51 ESs had a biallelic deletion (>20% by FISH and/or by MLPA) but with overexpressed miR-206,-381, and 671-5p, suggesting intratumoral heterogeneity, i.e., both genetic and epigenetic regulation. At least threefold overexpression of one of miR-206,-381, and 671-5p was detected in all MPNSTs, EMCSs, SSs and 7 MCs. Except for ESs, four SSs and one MPNST, there was no event above threefold overexpression of miR-765 among all 195 tested tumors. Our results suggest a general role of miR-206,-381, and 671-5p in SMARCB1 gene silencing of ES, MC, EMCS, MPNST and SS. In the future, miR-765 could possibly be a diagnostic tool for ES because of its 97% specificity and 80% sensitivity. © 2016 Wiley Periodicals, Inc.

Expression of F-actin-capping protein subunit beta, CAPZB, is associated with cell growth and motility in epithelioid sarcoma.

BACKGROUND: A previous proteomics study demonstrated the overexpression of F-actin capping protein subunit beta (CAPZB) in tissue specimens of epithelioid sarcoma (EpiS). The aim of the present study was to elucidate the function of CAPZB in EpiS. METHODS: Cellular functional assays were performed in two EpiS cell lines using CAPZB siRNAs. In addition, comparative protein expression analyses using Isobaric Tags for Relative and Absolute Quantitation (i-TRAQ) method were performed to identify the specific proteins whose expression was dysregulated by CAPZB, and analysed the data with the Ingenuity Pathways Analysis (IPA) system using the obtained protein profiles to clarify the functional pathway networks associated with the oncogenic function of CAPZB in EpiS. Additionally, we performed functional assays of the INI1 protein using INI1-overexpressing EpiS cells. RESULTS: All 15 EpiS cases showed an immunohistochemical expression of CAPZB, and two EpiS cell lines exhibited a strong CAPZB expression. Silencing of CAPZB inhibited the growth, invasion and migration of the EpiS cells. Analysis of protein profiles using the IPA system suggested that SWI/SNF chromatin-remodeling complexes including INI1 may function as a possible upstream regulator of CAPZB. Furthermore, silencing of CAPZB resulted in a decreased expression of INI1 proteins in the INI1-positive EpiS cells, whereas the induction of INI1 in the INI1-deficient EpiS cells resulted in an increased CAPZB mRNA expression. CONCLUSIONS: CAPZB is involved in tumor progression in cases of EpiS, irrespective of the INI1 expression, and may be a potential therapeutic target. The paradoxical relationship between the tumor suppressor INI1 and the oncoprotein CAPZB in the pathogenesis of EpiS remains to be clarified.