Utilization of p53 and p16 Immunohistochemistry in the Classification of Human Papillomavirus-Associated, p53 Wild-Type, and p53 Abnormal Oral Epithelial Dysplasia.

p53 immunohistochemistry (IHC) has recently been shown to be a clinically useful marker for predicting risk of progression to invasive squamous cell carcinoma in oral epithelial dysplasia (OED). The literature supports the use of p53 IHC as a marker to identify TP53 mutation in in situ and invasive vulvar lesions and as a surrogate marker for high-risk human papillomavirus (HPV) infection, but there is little documentation for similar use in OED. The purpose of this study was to determine whether p53 IHC is a reliable surrogate marker for detecting both TP53 mutation and high-risk HPV infection in OED. We studied 57 cases of OED (11 mild, 18 moderate, and 28 severe), and all were stained for p16 and p53 IHC. High-risk HPV RNA in situ hybridization (ISH) was performed in selected cases (all p16-positive cases and all OED showing abundant apoptotic cells and karyorrhectic cells; N = 27). Targeted next-generation sequencing (NGS) was performed in 33 p16-negative cases and all high-risk HPV RNA ISH-negative cases (N = 36). We identified 21 cases with p53 basal sparing patterns (mid-epithelial and markedly reduced [null-like]), 14 cases with p53 wild-type patterns (scattered basal and patchy basal/parabasal), and 22 cases with p53 abnormal patterns (18 overexpression, 3 null, and 1 novel cytoplasmic pattern). Among cases with p53 basal sparing patterns, 20 were positive for p16 (20/21, 95%), and all were positive for high-risk HPV RNA ISH (21/21, 100%). The 36 sequenced cases had IHC patterns concordant with TP53 mutation status in 92% (33/36) of lesions. This study demonstrates that p53 IHC expression patterns are sensitive and specific for detection of both high-risk HPV infection and TP53 mutation. Coupled with selective p16 IHC testing, this IHC panel can accurately subclassify OED into HPV-associated, p53 wild-type (conventional), and p53 abnormal OED.

Abnormal p53 Immunohistochemical Patterns Shed Light on the Aggressiveness of Oral Epithelial Dysplasia.

The diagnosis of oral epithelial dysplasia is based on the degree of architectural and cytologic atypia in the squamous epithelium. The conventional grading system of mild, moderate, and severe dysplasia is considered by many the gold standard in predicting the risk of malignant transformation. Unfortunately, some low-grade lesions, with or without dysplasia, progress to squamous cell carcinoma (SCC) in short periods. As a result, we are proposing a new approach to characterize oral dysplastic lesions that will help identify lesions at high risk for malignant transformation. We included a total of 203 cases of oral epithelial dysplasia, proliferative verrucous leukoplakia, lichenoid, and commonly observed mucosal reactive lesions to evaluate their p53 immunohistochemical (IHC) staining patterns. We identified 4 wild-type patterns, including scattered basal, patchy basal/parabasal, null-like/basal sparing, mid-epithelial/basal sparing, and 3 abnormal p53 patterns, including overexpression basal/parabasal only, overexpression basal/parabasal to diffuse, and null. All cases of lichenoid and reactive lesions exhibited scattered basal or patchy basal/parabasal patterns, whereas human papillomavirus-associated oral epithelial dysplasia demonstrated null-like/basal sparing or mid-epithelial/basal sparing patterns. Of the oral epithelial dysplasia cases, 42.5% (51/120) demonstrated an abnormal p53 IHC pattern. p53 abnormal oral epithelial dysplasia was significantly more likely to progress to invasive SCC when compared to p53 wild-type oral epithelial dysplasia (21.6% vs 0%, P < .0001). Furthermore, p53 abnormal oral epithelial dysplasia was more likely to have dyskeratosis and/or acantholysis (98.0% vs 43.5%, P < .0001). We propose the term p53 abnormal oral epithelial dysplasia to highlight the importance of utilizing p53 IHC stain to recognize lesions that are at high risk of progression to invasive disease, irrespective of the histologic grade, and propose that these lesions should not be graded using the conventional grading system to avoid delayed management.

Diagnosis of Fusion-Associated Sarcomas by Exon Expression Imbalance and Gene Expression.

Sarcomas are a diverse group of tumors, with >70 subtypes in the current World Health Organization classification, each with distinct biological behavior requiring specific clinical management. A significant portion of sarcomas are molecularly defined by expression of a driver fusion gene; identification of such fusions is the basis of molecular diagnostics in sarcomas, which is of increasing complexity due to the ongoing discovery of new gene fusions. Recently, a multiplex NanoString platform-based assay was developed and clinically implemented, with fusion junction-spanning probes that detect the majority of sarcoma fusion types, with high sensitivity and specificity, and with lower cost and shorter turnaround time than those of targeted next-generation sequencing-based alternatives. Despite the effectiveness of this assay, there are several entities for which fusion-junction probes are not suitable due to multiple possible gene partners or excessive variability at the exon junctions. Here, the development and evaluation of a companion assay are described that uses NanoString-based gene expression analysis to detect aberrant 3'/5' exon expression imbalance and/or total gene overexpression as a surrogate marker for fusion gene rearrangement. This assay evaluates exon imbalance in 23 genes involved in over 25 mesenchymal tumor types and five genes specific to sarcomas with CIC rearrangements. Based on evaluation of 115 retrospectively and 91 prospectively collected cases, an assay sensitivity of 92.8% and specificity of 93.5% are demonstrated.

NUTM1 -rearranged Carcinoma of the Thyroid : A Distinct Subset of NUT Carcinoma Characterized by Frequent NSD3 - NUTM1 Fusions.

NUT carcinoma (NC) is a rare subtype of squamous cell carcinoma defined by NUTM1 rearrangements encoding NUT fusion oncoproteins (the most frequent fusion partner being BRD4 ) that carries a very poor prognosis, with most patients dying in under 1 year. Only rare primary thyroid NCs have been reported. Here, we evaluated a series of 14 cases. The median patient age at diagnosis was 38 years (range: 17 to 72 y). Eight of 13 cases with slides available for review (62%) showed a morphology typical of NC, whereas 5 (38%) had a non-NC-like morphology, some of which had areas of cribriform or fused follicular architecture resembling a follicular cell-derived thyroid carcinoma. For cases with immunohistochemistry results, 85% (11/13) were positive for NUT on biopsy or resection, though staining was significantly decreased on resection specimens due to fixation; 55% (6/11) were positive for PAX8, and 54% (7/13) for TTF-1. Tumors with a non-NC-like morphology were all positive for PAX8 and TTF-1. The fusion partner was known in 12 cases: 9 (75%) cases had a NSD3-NUTM1 fusion, and 3 (25%) had a BRD4-NUTM1 fusion. For our cohort, the 2-year overall survival (OS) was 69%, and the 5-year OS was 58%. Patients with NC-like tumors had a significantly worse OS compared with that of patients with tumors with a non-NC-like morphology ( P =0.0462). Our study shows that NC of the thyroid can mimic other thyroid primaries, has a high rate of NSD3 - NUTM1 fusions, and an overall more protracted clinical course compared with nonthyroid primary NC.

Cobalt ions induce metabolic stress in synovial fibroblasts and secretion of cytokines/chemokines that may be diagnostic markers for adverse local tissue reactions to hip implants.

Adverse local tissue reactions (ALTRs) are a prominent cause of hip implant failure. ALTRs are characterized by aseptic necrosis and leukocyte infiltration of synovial tissue. The prevalence of ALTRs in hips with failing metal implants, with highest rates occurring in patients with metal-on-metal articulations, suggests a role for CoCrMo corrosion in ALTR formation. Although hypersensitivity reactions are the most accepted etiology, the precise cellular mechanism driving ALTR pathogenesis remains enigmatic. Here we show that cobalt ions released by failing hip implants induce mitochondrial stress and cytokine secretion by synovial fibroblasts: the presumptive initiators of ALTR pathogenesis. We found that in-vitro treatment of synovial fibroblasts with cobalt, but not chromium, generated gene expression changes indicative of hypoxia and mitophagy responses also observed in ALTRs biopsies. Inflammatory factors secreted by cobalt-exposed synovial fibroblasts were among those most concentrated in ALTR synovial fluid. Furthermore, both conditioned media from cobalt-exposed synovial fibroblasts, and synovial fluid from ALTRs patients, elicit endothelial activation and monocyte migration. Finally, we identify the IL16/CTACK ratio in synovial fluid as a possible diagnostic marker of ALTRs. Our results provide evidence suggesting that metal ions induce cell stress in synovial fibroblasts that promote an inflammatory response consistent with initiating ALTR formation. STATEMENT OF SIGNIFICANCE: We demonstrate that the cytotoxic effects of cobalt ions on the synovial cells (fibroblast) is sufficient to trigger inflammation on hip joints with metal implants. Cobalt ions affect mitochondrial function, leading to the auto phagocytosis of mitochondria and trigger a hypoxic response. The cell's hypoxic response includes secretion of cytokines that are capable of trigger inflammation by activating blood vessels and enhancing leukocyte migration. Among the secreted cytokines is IL-16, which is highly concentrated in the synovial fluid of the patients with adverse local tissue reactions and could be use as diagnostic marker. In conclusion we define the cells of the hip joint as key players in triggering the adverse reactions to hip implants and providing biomarkers for early diagnosis of adverse reactions to hip implants.

Perivascular lymphocytic aggregates in hip prosthesis-associated adverse local tissue reactions demonstrate Th1 and Th2 activity and exhausted CD8+ cell responses.

Hip implants are a successful solution for osteoarthritis; however, some individuals with metal-on-metal (MoM) and metal-on-polyethylene (MoP) prosthetics develop adverse local tissue reactions (ALTRs). While MoM and MoP ALTRs are presumed to be delayed hypersensitivity reactions to corrosion products, MoM- and MoP-associated ALTRs present with different histological characteristics. We compared MoM- and MoP-associated ALTRs histopathology with cobalt and chromium levels in serum and synovial fluid. We analyzed the gene expression levels of leukocyte aggregates and synovial fluid chemokines/cytokines to resolve potential pathophysiologic differences. In addition, we classified ALTRs from 79 patients according to their leukocyte infiltrates as macrophage-dominant, mixed, and lymphocyte-dominant. Immune-related transcript profiles from lymphocyte-dominant MoM- and MoP-associated ALTR patients with perivascular lymphocytic aggregates were similar. Cell signatures indicated predominantly macrophage, Th1 and Th2 lymphocytic infiltrate, with strong exhausted CD8+ signature, and low Th17 and B cell, relative to healthy lymph nodes. Lymphocyte-dominant ALTR-associated synovial fluid contained higher levels of induced protein 10 (IP-10), interleukin-1 receptor antagonist (IL-1RN), IL-8, IL-6, IL-16, macrophage inflammatory protein 1 (MIP-1α), IL-18, MCP-2, and lower cell-attracting chemokine levels, when compared with prosthetic revisions lacking ALTRs. In addition, the higher levels of IP-10, IL-8, IL-6, MIP-1α, and MCP-2 were observed within the synovial fluid of the lymphocyte-dominant ALTRs relative to the macrophage-dominant ALTRs. Not all cytokines/chemokines were detected in the perivascular aggregate transcripts, suggesting the existence of other sources in the affected synovia. Our results support the hypothesis of common hypersensitivity pathogenesis in lymphocyte-dominant MoM and MoP ALTRs. The exhausted lymphocyte signature indicates chronic processes and an impaired immune response, although the cause of the persistent T-cell activation remains unclear. The cytokine/chemokine signature of lymphocyte-dominant-associated ATLRs may be of utility for diagnosing this more aggressive pathogenesis.

Muscle invasion in oropharyngeal carcinoma undergoing transoral robotic surgery.

BACKGROUNDS: Pathologic features of oropharyngeal squamous cell carcinoma (OPSCC) treated with trans-oral robotic surgery predict prognosis and adjuvant therapy. We hypothesized that pathologic muscle invasion (pMI) is associated with poor pathological markers. METHODS: Retrospective review of surgically treated OPSCC to identify pMI and its association with poor pathologic markers. RESULTS: pMI was present in 12/37 patients, and compared to non-pMI, was associated with higher rates of lymphovascular invasion (75% vs. 36%, p = 0.03), perineural invasion (16.7% vs. 0%, p = 0.04), extranodal extension (66.7% vs. 20%, p < 0.01), and tumor stage (8.3% vs. 48% pT1, 75% vs. 52% pT2 and 16.7% vs. 0% pT3). pMI was associated with having a positive margin on main specimen (41.7% vs. 12%, p = 0.04) but not after considering additional margins. CONCLUSIONS: Muscle invasion was associated with higher pathologic tumor staging, poor pathologic factors, and higher rates of positive margin on main specimen.

A Rapid and Cost-Effective Gene Expression Assay for the Diagnosis of Well-Differentiated and Dedifferentiated Liposarcomas.

Histologic examination neither reliably distinguishes benign lipomas from atypical lipomatous tumor/well-differentiated liposarcoma, nor dedifferentiated liposarcoma from other pleomorphic sarcomas, entities with different prognoses and management. Molecular confirmation of pathognomonic 12q13-15 amplifications leading to MDM2 overexpression is a diagnostic gold standard. Currently the most commonly used assay for this purpose is fluorescence in situ hybridization (FISH), but this is labor intensive. This study assessed whether newer NanoString-based technology could allow for more rapid and cost-efficient diagnosis of liposarcomas on standard formalin-fixed tissues through gene expression. Leveraging large-scale transcriptome data from The Cancer Genome Atlas, 20 genes were identified, most from the 12q13-15 amplicon, that distinguish dedifferentiated liposarcoma from other sarcomas and can be measured within a single NanoString assay. Using 21 cases of histologically ambiguous low-grade adipocytic tumors with available MDM2 amplification status, a machine learning-based analytical pipeline was built that assigns a given sample as negative or positive for liposarcoma based on quantitative gene expression. The effectiveness of the assay was validated on an independent set of 100 sarcoma samples (including 40 incident prospective cases), where histologic examination was considered insufficient for clinical diagnosis. The NanoString assay had a 93% technical success rate, and an accuracy of 97.8% versus an MDM2 amplification FISH gold standard. NanoString had a considerably faster turnaround time and was cheaper than FISH.

p53 immunohistochemical analysis of fusion-positive uterine sarcomas.

AIMS: Uterine sarcomas can be grouped into tumours with pathognomonic genetic fusions such as low-grade endometrial stromal sarcoma (LGESS), high-grade endometrial stromal sarcoma (HGESS), and inflammatory myofibroblastic tumour (IMT), and tumours lacking genetic fusions such as leiomyosarcoma (LMS) and undifferentiated uterine sarcoma (UUS). Members of the latter group frequently harbour TP53 mutations. The aim of this study was to evaluate TP53 mutations by the use of immunohistochemistry in fusion-positive uterine sarcomas. METHODS AND RESULTS: We performed p53 immunohistochemical staining on 124 uterine sarcomas harbouring genetic fusions and 38 fusion-negative LMSs and UUSs. These included 41 HGESSs with YWHAE, BCOR and BCORL1 fusions/rearrangements, 13 IMTs with ALK fusion, 12 sarcomas with NTRK1/3 fusion, three sarcomas with PDGFB fusion, and 55 LGESSs with JAZF1, SUZ12 and PHF1 fusions/rearrangements. All HGESSs, LGESSs, IMTs and sarcomas with PDGFB fusion showed wild-type p53 expression. Among NTRK1/3-positive sarcomas, a TPR-NTRK1-positive sarcoma with nuclear pleomorphism showed mutation-type p53 expression. The remaining 11 NTRK1/3-positive sarcomas showed wild-type p53 expression, except for the subclonal p53 mutation-type staining in a minor pleomorphic focus of an NTRK3-positive sarcoma. Twenty-one of 27 (78%) LMSs and six of nine (67%) UUSs showed mutation-type p53 expression. CONCLUSION: p53 immunohistochemistry may be considered in the initial work-up of a uterine sarcoma, as mutation-type staining would make a fusion-positive sarcoma very unlikely. Mutation-type p53 expression, however, can be seen in a small subset of NTRK1/3-positive sarcomas showing pleomorphic round/ovoid cell histology, which may represent a mechanism of progression in these tumours.

Sclerosing Odontogenic Carcinoma with Local Recurrence: Case Report and Review of Literature.

Sclerosing odontogenic carcinoma is a rare locally destructive neoplasm with many histologic mimics. Here the diagnostic challenges are presented of a case of sclerosing odontogenic carcinoma with variable histologic features, including unusual and unexpected negative immunostaining for CK19.

Molecular Profiling of Hyalinizing Clear Cell Carcinomas Revealed a Subset of Tumors Harboring a Novel EWSR1-CREM Fusion: Report of 3 Cases.

We describe a novel gene fusion, EWSR1-CREM, identified in 3 cases of clear cell carcinoma (CCC) using anchored multiplex polymerase chain reaction, a next-generation sequencing-based technique. CCC is a low-grade salivary tumor recently characterized to have EWSR1-ATF1 fusions in the majority of cases. Three cases of malignant tumor presenting in the base of tongue, lung, and nasopharynx were studied. All cases shared a clear cell morphology with hyalinized stroma, presence of mucin and p63 positivity and were initially diagnosed as mucoepidermoid carcinoma but were negative for evidence of any of the expected gene fusions. Anchored multiplex polymerase chain reaction demonstrated a EWSR1-CREM fusion in all 3 cases to confirm a diagnosis of CCC. This finding is biologically justified as CREM and ATF1 both belong to the CREB family of transcription factors. EWSR1-CREM fusions have not been previously reported in CCC and have only rarely been reported in other tumors. We show that the ability to discover novel gene variants with next-generation sequencing-based assays has clinical utility in the pathologic classification of fusion gene-associated tumors.

BCOR Internal Tandem Duplication in High-grade Uterine Sarcomas.

Endometrial stromal sarcomas (ESSs) are mesenchymal uterine tumors characterized by recurrent genetic events, most commonly chromosomal rearrangements, that create oncogenic gene fusions. High-grade endometrial stromal sarcomas (HG-ESSs), as defined in the 2014 World Health Organization Classification, typically contain oncogenic YWHAE-NUTM2 fusions; however, although not well characterized, there are tumors morphologically overlapping with HG-ESS that do not contain the YWHAE-NUTM2 fusions. These fusions are also found in certain pediatric primitive sarcomas, including clear cell sarcoma of the kidney and soft tissue undifferentiated round cell sarcoma of infancy. A subset of these same pediatric sarcomas lack YWHAE-NUTM2 fusions and instead have internal tandem duplications (ITDs) involving exon 15 of BCOR (BCOR ITD). We investigated the presence of BCOR ITD by targeted sequencing in a series of 31 uterine sarcomas, comprising 5 low-grade ESS, 13 uterine sarcomas diagnosed as HG-ESS, and 13 undifferentiated uterine sarcomas. BCOR ITD were present in 1 uterine sarcoma diagnosed as HG-ESS and 2 undifferentiated sarcomas with uniform nuclear features, all of which lacked any of the recurrent chromosome translocations known to occur in ESS. These 3 high-grade sarcomas with BCOR ITD affected young patients (average age, 24) and morphologically were composed of nonpleomorphic spindle cells admixed with epithelioid and round cell areas. Focal myxoid stroma was present in 2 cases. Mitotic activity was brisk, necrosis was present, and there was lymphovascular involvement in all cases. The 3 uterine sarcomas with BCOR ITD exhibited diffuse cyclin D1 immunohistochemical expression and there was diffuse BCOR expression in the 2 cases tested. Long-term follow-up in 2 patients revealed 1 to be tumor-free after 22 years and the other to die of disease after 8 years. In conclusion, BCOR ITD is an oncogenic alternative to YWHAE-NUTM2 fusion in high-grade uterine sarcomas with uniform nuclear features. We propose that neoplasms with the morphology described and BCOR ITD be regarded as a unique subtype of high-grade uterine sarcoma, possibly within the family of endometrial stromal neoplasia.

Development and Evaluation of a Pan-Sarcoma Fusion Gene Detection Assay Using the NanoString nCounter Platform.

The NanoString nCounter assay is a high-throughput hybridization technique using target-specific probes that can be customized to test for numerous fusion transcripts in a single assay using RNA from formalin-fixed, paraffin-embedded material. We designed a NanoString assay targeting 174 unique fusion junctions in 25 sarcoma types. The study cohort comprised 212 cases, 96 of which showed fusion gene expression by the NanoString assay, including all 20 Ewing sarcomas, 11 synovial sarcomas, and 5 myxoid liposarcomas tested. Among these 96 cases, 15 showed fusion expression not identified by standard clinical assay, including EWSR1-FLI1, EWSR1-ERG, BCOR-CCNB3, ZC3H7B-BCOR, HEY1-NCOA2, CIC-DUX4, COL1A1-PDGFB, MYH9-USP6, YAP1-TFE3, and IRF2BP2-CDX1 fusions. There were no false-positive results; however, four cases were false negative when compared with clinically available fluorescence in situ hybridization or RT-PCR testing. When batched as six cases, the per-sample reagent cost was less than conventional techniques, such as fluorescence in situ hybridization, with technologist hands-on time of 1.2 hours per case and assay time of 36 hours. In summary, the NanoString nCounter Sarcoma Fusion CodeSet reliably and cost-effectively identifies fusion genes in sarcomas using formalin-fixed, paraffin-embedded material, including many fusions missed by standard clinical assays, and can serve as a first-line clinical diagnostic test for sarcoma fusion gene identification, replacing multiple individual clinical assays.

Ectopic thymoma managed by neck dissection & video-assisted thoracoscopic thymectomy.

Ectopic thymoma in the neck is a rare phenomenon, with fewer than 20 cases reported worldwide. Evidence for management of ectopic thymoma comes from literature for mediastinal thymoma despite clinical features that distinguish the two. Here we present a case of a 31-year-old female with an asymptomatic neck mass who was found to have an ectopic cervical thymoma with concomitant mediastinal thymic hyperplasia. The decision was made to perform a left-sided neck dissection and a video-assisted thoracoscopic surgery (VATS) thymectomy. We suggest that this approach be considered for a minimally invasive management of this rare but important condition.

ETV6-NTRK3 Is Expressed in a Subset of ALK-Negative Inflammatory Myofibroblastic Tumors.

Inflammatory myofibroblastic tumor (IMT) is a genetically heterogenous tumor of the viscera and soft tissues, with multiple molecular features having been demonstrated in this tumor type. About 50% of cases harbor an anaplastic lymphoma kinase (ALK) gene rearrangement, and recent studies have described novel fusions involving the ROS1 and PDGFRß genes in a subset of ALK-negative cases. However, the molecular features of the remaining subset of cases are not yet defined. We report a case of a large, highly aggressive IMT of the lung in a 17-year-old girl. This case was molecularly characterized through whole-genome and transcriptome sequencing. Subsequently, we investigated a cohort of 15 ALK-negative IMTs of various anatomic sites. All cases were screened using fluorescence in situ hybridization (FISH) for rearrangement of the ETV6 locus and with reverse transcription polymerase chain reaction (RT-PCR) for the ETV6-NTRK3 fusion transcript. Whole-genome and transcriptome sequencing revealed an ETV6-NTRK3 fusion transcript in our index case. This was confirmed by FISH studies for ETV6 gene rearrangement, as well as by RT-PCR. In addition, 2 additional cases in our cohort demonstrated ETV6 rearrangement by FISH. The presence of ETV6-NTRK3 fusion transcript was demonstrated by RT-PCR in one of these additional cases. In summary, we demonstrate the expression of the ETV6-NTRK3 fusion oncogene in a small subset of IMTs, lending further support to the role of oncogenic tyrosine kinases in the pathophysiology of this tumor type. Our data also further expand the growing spectrum of tumor types expressing the ETV6-NTRK3 fusion.

The application of next-generation sequencing-based molecular diagnostics in endometrial stromal sarcoma.

AIMS: Endometrial stromal sarcomas (ESSs) are divided into low-grade and high-grade subtypes, with the latter showing more aggressive clinical behaviour. Although histology and immunophenotype can aid in the diagnosis of these tumours, genetic studies can provide additional diagnostic insights, as low-grade ESSs frequently harbour fusions involving JAZF1/SUZ12 and/or JAZF1/PHF1, whereas high-grade ESSs are defined by YWHAE-NUTM2A/B fusions. The aim of this study was to evaluate the utility of a next-generation sequencing (NGS)-based assay in identifying ESS fusions in archival formalin-fixed paraffin-embedded tumour samples. METHODS AND RESULTS: We applied an NGS-based fusion transcript detection assay (Archer FusionPlex Sarcoma Panel) that targets YWHAE and JAZF1 fusions in a series of low-grade ESSs (n = 11) and high-grade ESSs (n = 5) that were previously confirmed to harbour genetic rearrangements by fluorescence in-situ hybridization (FISH) and/or reverse transcription polymerase chain reaction (RT-PCR) analyses. The fusion assay identified junctional fusion transcript sequences that corresponded to the known FISH/RT-PCR results in all cases. Four low-grade ESSs harboured JAZF1-PHF1 fusions with different junctional sequences, and all were correctly identified because of the open-ended nature of the assay design, using anchored multiplex polymerase chain reaction. Seven non-ESS sarcomas were also included as negative controls, and no strong ESS fusion candidates were identified in these cases. CONCLUSIONS: Our findings demonstrate good sensitivity and specificity of an NGS-based gene fusion assay in the detection of ESS fusion transcripts.

Fine-needle aspiration of soft tissue myoepithelioma.

Soft tissue myoepithelioma is a rare neoplasm composed of myoepithelial cells. We describe the cytologic features of a soft tissue myoepithelioma arising in the right lower chest wall in a 65-year-old woman. The fine-needle aspiration (FNA) smears showed round to oval, spindle, epithelioid, and plasmacytoid cells in the myxoid background. The nuclei were uniform, round to ovoid, with finely distributed chromatin and eosinophilic or pale cytoplasm, and resembled lobular carcinoma of breast. Ultrasound guided core biopsy showed the tumor cells had bland cytologic features, arranged in small cords, nests, and dissociated single cells, with no glandular differentiation or breast tissue seen. The tumor cells demonstrated immunoreactivity for cytokeratin (AE1/AE3) and glial fibrillary acidic protein, but were negative for estrogen receptor. Fluorescence in situ hybridization demonstrated the EWSR1 rearrangement, confirming the diagnosis of myoepithelioma.

Nerve Bundles and Deep Dyspareunia in Endometriosis.

The etiology of deep dyspareunia in endometriosis is unclear. Our objective was to determine whether nerve bundle density in the cul-de-sac/uterosacrals (zone II) is associated with deep dyspareunia in women with endometriosis. We conducted a blinded retrospective immunohistochemistry study (n = 58) at a tertiary referral center (2011-2013). Patients were stringently phenotyped into a study group and 2 control groups. The study group (tender endometriosis, n = 29) consisted of patients with deep dyspareunia, a tender zone II on examination, and an endometriosis lesion in zone II excised at surgery. Control group 1 (nontender endometriosis, n = 17) consisted of patients without deep dyspareunia, a nontender zone II on examination, and an endometriosis lesion in zone II excised at surgery. Control group 2 (tender nonendometriosis, n = 12) consisted of patients with deep dyspareunia, a tender zone II on examination, and a nonendometriosis lesion (eg, normal histology) in zone II excised at surgery. Protein gene product 9.5 (PGP9.5) immunohistochemistry was performed to identify nerve bundles (nerve fibers surrounded by perineurium) in the excised zone II lesion. PGP9.5 nerve bundle density (bundles/high powered field [HPF]) was then scored by a pathologist blinded to the group. We found a significant difference in PGP9.5 nerve bundle density between the 3 groups (analysis of variance, F2,55 = 6.39, P = .003). Mean PGP9.5 nerve bundle density was significantly higher in the study group (1.16 ± 0.56 bundles/HPF [±standard deviation]) compared to control group 1 (0.65 ± 0.36, Tukey test, P = .005) and control group 2 (0.72 ± 0.56, Tukey test, P = .044). This study provides evidence that neurogenesis in the cul-de-sac/uterosacrals may be an etiological factor for deep dyspareunia in endometriosis.

Malignant granular cell tumor of the foot-multimodality imaging findings and literature review.

We describe how the combination of imaging and histologic findings was essential in establishing a preoperative diagnosis of an extremely rare malignant granular cell tumor (GrCT) occurring in the lower extremity of a 17-year-old man. Magnetic resonance imaging demonstrated a large infiltrative tumor of heterogeneous intermediate signal intensity on both T1- and T2-weighted sequences. Subsequent computed tomography (CT) and fluorodeoxyglucose positron emission tomography CT scans of the patient revealed distant nodal and skeletal metastases.

Synthetic lethality screens reveal RPS6 and MST1R as modifiers of insulin-like growth factor-1 receptor inhibitor activity in childhood sarcomas.

The insulin-like growth factor-1 receptor (IGF1R) is emerging as a promising therapeutic target in human cancers. In the high-risk childhood sarcomas Ewing family tumor and rhabdomyosarcoma, IGF1R-blocking antibodies show impressive antitumor activity in some but not all patients, and acquired resistance is observed. Because tumor IGF1R mutations are not described, the basis of IGF1R inhibitor resistance remains unknown. We hypothesized that compensatory signaling cascades bypassing targeted IGF1R inhibition might be involved. To test this systematically, we performed small interfering RNA (siRNA) screens in sarcoma cell lines to identify IGF1R pathway components or related protein tyrosine kinase (PTK) networks that modulate the antitumor efficacy of the BMS-536924 IGF1R kinase inhibitor. This strategy revealed (a) that sarcoma cells are exquisitely sensitive to loss of distal rather than proximal IGF1R signaling components, such as ribosomal protein S6 (RPS6); (b) that BMS-536924 fails to block RPS6 activation in resistant sarcoma cell lines; and (c) that siRNA knockdown of the macrophage-stimulating 1 receptor tyrosine kinase (MST1R; also known as RON) restores BMS-536924 efficacy, even in highly drug-resistant cell lines. We confirmed MST1R expression across a broad panel of childhood sarcomas, and found that loss of MST1R by RNA interference blocks downstream RPS6 activation when combined with BMS-536924 in vitro. These findings underscore the importance of fully understanding PTK networks for successful clinical implementation of kinase inhibitor strategies.