Solid-Basaloid Adenoid Cystic Carcinoma of the Breast: An Aggressive Subtype Enriched for Notch Pathway and Chromatin Modifier Mutations With MYB Overexpression.

Adenoid cystic carcinoma (AdCC) is a rare triple-negative breast cancer analogous to its extramammary counterparts. Diagnosis of the more aggressive solid-basaloid variant of AdCC (SB-AdCC) can be challenging due to poorly defined histopathologic and molecular features. We characterized 22 invasive and in situ basaloid carcinomas by morphology, immunohistochemistry, genetics, and MYB status using multiple platforms and assessed clinical behavior and neoadjuvant chemotherapy responses. After consensus review, 16/22 cases were classified as SB-AdCC. All SB-AdCC had predominantly solid growth and at least focal myxohyaline stroma and were immune-poor. Eosinophilic squamoid cells (69%, 11/16) and basement membrane-like secretions (69%, 11/16) were common, and intercalated ducts (31%, 5/16) were less frequent. SB-AdCC typically expressed SOX10 (100%, 16/16) and luminal markers (100%, 16/16 CK7; 88%, 14/16 CD117; 93%, 13/14 CAM5.2). SMA (40%, 6/15) expression was less common, and SMM (27%, 3/11), GATA3 (20%, 3/15), and p63 (25%, 4/16) were mostly negative. MYB protein and/or MYB RNA overexpression was universal in evaluable cases (13/13), with RNA in situ hybridization (10/10) more reliable than immunohistochemistry (10/11, plus 4 excisions inconclusive). Fluorescence in situ hybridization and/or next-generation sequencing identified MYB rearrangements (20%, 3/15) and amplifications/copy gains (60%, 9/15) but no MYB::NFIB fusions. SB-AdCC often had aberrations in Notch pathway (60%, including 40% NOTCH1 and 20% NOTCH2) and/or chromatin modifier (60%, including 33% CREBBP) genes, with relatively infrequent TP53 mutations (27%). Unclassified invasive basaloid carcinomas lacking described histologic features of SB-AdCC (n = 4) and basaloid ductal carcinoma in situ (n = 2) showed similar immunoprofiles and genetics as SB-AdCC, including Notch aberrations and MYB overexpression with MYB rearrangements/amplifications. Overall, nodal (22%) and distant (33%) metastases were common, and 23% of patients died of disease (mean follow-up, 35 months; n = 22). Responses were poor in all 7 neoadjuvant chemotherapy-treated patients, without any achieving pathologic complete response. The data highlight the histopathologic spectrum of basaloid carcinomas including SB-AdCC and reveal shared genetics and MYB activation, which can be diagnostically useful. Aggressive behavior and poor treatment responses emphasize a need for additional treatment approaches.

Clinicopathologic Evaluation of CTNNB1 Mutations in High-Intermediate Risk Endometrial Endometrioid Carcinoma.

CTNNB1 mutations convey increased risk of recurrence in low-risk endometrial endometrioid carcinoma (EEC). Results from previous high-intermediate risk (HIR) cohorts are mixed. The aims of this study were to correlate CTNNB1 mutational status with clinical outcomes and to evaluate the relationship between CTNNB1 mutations and the 4 prognostic subgroups defined by The Cancer Genome Atlas in HIR EEC. CTNNB1 mutational status was determined by Sanger sequencing of exon 3 of the CTNNB1 gene. Mismatch repair, POLE , p53, and L1 cell-adhesion molecule (L1CAM) status were also evaluated. Descriptive statistics and survival analyses were performed. Eighty-eight cases of HIR EEC were identified, of which 22 (25%) were CTNNB1 mutant ( CTNNB1 -mut) and 66 (75%) were wild-type ( CTNNB1 -WT). Median follow-up was 60 mo. Recurrence occurred in 13/88 (15%) patients. Recurrence rates were not significantly different between patients with CTNNB1- mut and CTNNB1- WT tumors (14% vs. 15%, P =0.86). Recurrence-free survival and overall survival were not significantly different (recurrence-free survival hazard ratio: 0.97, 95% confidence interval: 0.27-3.52, P =0.96; overall survival hazard ratio: 0.23, 95% confidence interval: 0.03-1.71, P =0.15). Mismatch repair deficiency was more prevalent in CTNNB1 -WT compared with CTNNB1 -mut tumors (46% vs. 14%, P =0.01); prevalence of POLE mutations and aberrant p53 were not significantly different. In contrast to patients with low-risk EEC, no differences in recurrence or survival were found in patients with HIR EEC with CTNNB1- mut compared with CTNNB1 -WT tumors.

Prospective Clinical Prognostication of Endometrial Carcinomas Based on Next-Generation Sequencing and Immunohistochemistry-Real-World Implementation and Results at a Tertiary Care Center.

Based on findings from The Cancer Genome Atlas and the Proactive Molecular Risk Classifier for Endometrial Cancer algorithm, endometrial carcinoma can now be stratified into 4 prognostically distinct subgroups based on molecular alterations and immunohistochemical (IHC) aberrations. In this study, we describe the de novo adoption and clinical reporting of prognostic subgroup classification based on next-generation sequencing (NGS) and IHC analyses of all endometrial carcinoma resections at a single institution, framed by the Exploration, Preparation, Implementation, and Sustainment model. Results from the first 13 months show 188 tumors underwent analysis by a combination of IHC and a medium-sized (56 analyzed genes) NGS-based assay. All cases were assigned as either POLE (POLE-mutated) (5.3%), mismatch repair deficient (27.7%), no specific molecular profile (45.7%), or p53 abnormal (21.3%) inclusive of multiple-classifier cases. NGS-based analysis revealed additional distinctions among the subgroups, including reduced levels of PI3K pathway activation in the p53 abnormal subgroup, an increased rate of CTNNB1 activating mutation in the no specific molecular profile subgroup, and lower TP53 mutation variant allele frequencies in POLE and mismatch repair deficient subgroups compared with the p53 abnormal subgroup. Overall, we describe the testing protocol, reporting, and results of a combination of NGS and IHC to prospectively prognosticate endometrial carcinomas at a single tertiary care center.

Gastric-type endocervical adenocarcinoma and cervical cytology: Experience at a general hospital and review of the literature.

INTRODUCTION: Gastric-type endocervical adenocarcinoma (GAS) is an uncommon type of endocervical adenocarcinoma that is not associated with human papillomavirus infection. This diagnosis is relatively rare and may portend a worse prognosis than usual-type endocervical adenocarcinoma. Subtle morphological features make it an under-recognised diagnostic challenge. Study of the cytological features of individual cases is valuable in order to increase awareness of this entity. METHODS: The pathology database of our institution was searched for the diagnosis of GAS and all cytological and surgical specimens for each patient were reviewed. The original cytological interpretation was compared to a retrospective central review interpretation. Clinical history and follow-up results were obtained from the electronic medical record. RESULTS: Four cases of GAS were identified. The findings on initial cervical cytology varied, with GAS found in both patients with negative cervical cytology and those with atypical glandular cells. Cytological findings included endocervical cells arranged in three-dimensional clusters and honeycomb sheets with abundant vacuolar cytoplasm, and in two patients, moderate nuclear atypia with irregular nuclear membranes, coarse chromatin, hyperchromatic nuclei, and prominent nucleoli. In one patient, GAS was incidentally discovered via thorough sampling of a cystic lesion in the superior portion of the endocervical canal. CONCLUSIONS: GAS is an aggressive human papillomavirus-independent type of endocervical adenocarcinoma with subtle morphological features and, as our study shows, varying clinical presentation. Given the aggressive nature of GAS and the difficulties in initial diagnosis, increased awareness of this entity among pathologists is crucial.

Struma ovarii with atypical features and synchronous primary thyroid cancer: a case report and review of the literature.

PURPOSE: To present a case of struma ovarii with a typical features and synchronous primary thyroid carcinoma and review the available literature to guide diagnosis and management of these tumors. METHODS: We present a case from our hospital of a 55-year-old woman who had an adnexal mass with features concerning for papillary thyroid carcinoma and was ultimately determined to be struma ovarii with atypical features. Subsequent thyroid imaging and biopsy revealed a primary cervical thyroid carcinoma. We performed a PubMed search of published English language articles using the search terms "malignant struma ovarii," "metastatic struma ovarii," "struma ovarii with malignant transformation," "struma ovarii papillary thyroid carcinoma," "struma ovarii follicular thyroid carcinoma," and "struma ovarii with concurrent primary thyroid carcinoma." RESULTS: Literature review included 104 studies with a total of 195 patient cases. The average age at presentation was 44.9 years. 25.1% of patients had metastatic disease at presentation, and 6.2% had synchronous primary carcinomas; all of which were located in the thyroid. CONCLUSIONS: Thyroid carcinoma arising in struma ovarii or mature cystic teratoma should prompt clinical evaluation and imaging of the thyroid given the possibility of synchronous primaries, metastases, and recurrence.

Mucosal Proliferations in Completely Examined Fallopian Tubes Accompanying Ovarian Low-grade Serous Tumors: Neoplastic Precursor Lesions or Normal Variants of Benign Mucosa?

Malignant transformation of the fallopian tube mucosa, followed by exfoliation of malignant cells onto ovarian and/or peritoneal surfaces, has been implicated as the origin of most pelvic high-grade serous carcinoma. Whether a parallel pathway exists for pelvic low-grade serous tumors [ovarian serous borderline tumor (SBT) and low-grade serous carcinoma (LGSC)] remains to be fully elucidated. The literature is challenging to interpret due to variation in the diagnostic criteria and terminology for cytologically low-grade proliferations of the fallopian tube mucosa, as well as variation in fallopian tube specimen sampling. Recently, a candidate fallopian tube precursor to ovarian SBT, so-called papillary tubal hyperplasia, was described in advanced stage patients. The current study was designed to identify fallopian tube mucosal proliferations unique to patients with low-grade serous ovarian tumors (serous cystadenoma, SBT, LGSC) and to determine if they may represent precursors to the ovarian tumors. Fallopian tubes were thinly sliced and entirely examined microscopically, including all of the fimbriated and nonfimbriated portions of the tubes, from patients with ovarian serous cystadenoma (35), SBT (61), and LGSC (11) and from a control population of patients with ovarian mucinous cystadenoma (28), mature cystic teratoma (18) or uterine leiomyoma (14). The slides of the fallopian tubes were examined in randomized order, without knowledge of the clinical history or findings in the ovaries or other organs. Alterations of the mucosa of the fallopian tube were classified as type 1: nonpapillary proliferation of cytologically bland tubal epithelium exhibiting crowding, stratification, and/or tufting without papillary fibrovascular cores or as type 2: papillary alterations consisting of a fibrovascular core lined by a cytologically bland layer of tubal epithelium. A third abnormality, type 3, consisted of detached intraluminal papillae, buds, or nests of epithelium that cytologically resembled the epithelial component of SBT or LGSC. Mucosal proliferations were identified in subsets of all populations, including the control populations. Overall, type 1 proliferations were in 28% to 61% of all patients and type 2 alterations in 4% to 16%. There was no statistically significant difference in the incidence of type 1 or type 2 proliferations between the class of ovarian serous tumors (benign, SBT, LGSC), between early and advanced stage SBT, or between patients with any ovarian serous tumor and the control population of nonserous diagnoses. Type 3 alterations were only identified in patients with advanced stage SBT/LGSC and not in any early stage SBT or cystadenoma. These findings suggest that type 3 alterations floating in the fallopian tube lumen represent exfoliation of tumor cells from ovarian and/or peritoneal origin. Our study did not identify a mucosal-based proliferation of the fallopian tubes that was specific to ovarian low-grade serous tumors. Cytologically bland mucosal proliferations appear to be common in fallopian tubes from patients of all ages and unrelated to ovarian tumorigenesis. A consensus on diagnostic criteria and terminology for these types of proliferations is needed, as well as further study into their etiology, including possible association with hormonal environment.

Sentinel lymph node mapping and staging in endometrial cancer: A Society of Gynecologic Oncology literature review with consensus recommendations.

The emphasis in contemporary medical oncology has been "precision" or "personalized" medicine, terms that imply a strategy to improve efficacy through targeted therapies. Similar attempts at precision are occurring in surgical oncology. Sentinel lymph node (SLN) mapping has recently been introduced into the surgical staging of endometrial cancer with the goal to reduce morbidity associated with comprehensive lymphadenectomy, yet obtain prognostic information from lymph node status. The Society of Gynecologic Oncology's (SGO) Clinical Practice Committee and SLN Working Group reviewed the current literature for preparation of this document. Literature-based recommendations for the inclusion of SLN assessment in the treatment of patients with endometrial cancer are presented. This article examines.

The spatial structure of the tumor immune microenvironment can explain and predict patient response in high-grade serous carcinoma.

Despite ovarian cancer being the deadliest gynecological malignancy, there has been little change to therapeutic options and mortality rates over the last three decades. Recent studies indicate that the composition of the tumor immune microenvironment (TIME) influences patient outcomes but are limited by a lack of spatial understanding. We performed multiplexed ion beam imaging (MIBI) on 83 human high-grade serous carcinoma tumors - one of the largest protein-based, spatially-intact, single-cell resolution tumor datasets assembled - and used statistical and machine learning approaches to connect features of the TIME spatial organization to patient outcomes. Along with traditional clinical/immunohistochemical attributes and indicators of TIME composition, we found that several features of TIME spatial organization had significant univariate correlations and/or high relative importance in high-dimensional predictive models. The top performing predictive model for patient progression-free survival (PFS) used a combination of TIME composition and spatial features. Results demonstrate the importance of spatial structure in understanding how the TIME contributes to treatment outcomes. Furthermore, the present study provides a generalizable roadmap for spatial analyses of the TIME in ovarian cancer research.

It Does Exist! Diagnosis and Management of Thyroid Carcinomas Originating in Struma Ovarii.

Thyroid carcinoma originating in struma ovarii comprises a small minority of all cases of struma ovarii. Given the rarity of this diagnosis, literature to guide evaluation and management is limited. The most common carcinoma originating from struma ovarii is papillary thyroid carcinoma. Treatment includes surgery, including a fertility sparing approach if disease is confined to the ovary, with consideration of total thyroidectomy and radioactive iodine ablation for high-risk pathologic features or disease spread beyond the ovary. This review discusses the histopathologic findings, molecular pathology, clinical implications and management, and prognosis of thyroid carcinomas originating in struma ovarii.

Combination CDC-like kinase inhibition (CLK)/Dual-specificity tyrosine-regulated kinase (DYRK) and taxane therapy in CTNNB1-mutated endometrial cancer.

SM08502 (cirtuvivint) is a novel pan CDC-like kinase (CLK) and Dual specificity tyrosine kinase (DYRK) inhibitor that targets mRNA splicing and is optimized for Wnt pathway inhibition. Previous evaluation of single agent CLK/DYRK inhibition (SM04690) demonstrated inhibition of tumor progression and ß-catenin/TCF transcriptional activity in CTNNB1-mutant endometrial cancer (EC). In-vitro analysis of SM08502 similarly decreases Wnt transcriptional activity and cellular proliferation while increasing cellular apoptosis. SM08502 is an active single-agent therapy with IC50's in the nanomolar range for all EC cell lines evaluated. Combination of SM08502 with paclitaxel has synergistic effect in vitro, as demonstrated by Combination Index <1, and inhibits tumor progression in four endometrial cancer models (HEC265, Ishikawa, Ishikawa-S33Y, and SNGM). In our in vivo mouse models, Ishikawa demonstrated significantly lower tumor volumes of combination vs SM08502 alone (Repeated Measures one-way ANOVA, p = 0.04), but not vs paclitaxel alone. HEC265, SNGM, and Ishikawa-S33Y tumors all had significantly lower tumor volumes with combination SM08502 and paclitaxel compared to single-agent paclitaxel (Repeated Measures one-way ANOVA, p = 0.01, 0.004, and 0.0008, respectively) or single-agent SM08502 (Repeated Measures one-way ANOVA, p = 0.002, 0.005, and 0.01, respectively) alone. Mechanistically, treatment with SM08502 increases alternative splicing (AS) events compared to treatment with paclitaxel. AS regulation is an important post-transcriptional mechanism associated with the oncogenic process in many cancers, including EC. Results from these studies have led to a Phase I evaluation of this combination in recurrent EC.

Does Lymph Node Dissection Impact Adjuvant Treatment or Survival Outcomes in High-Risk Endometrial Cancers?

Objectives Lymphadenectomy does not improve overall survival outcomes in patients with low-risk endometrial cancers. Sentinel node mapping has a high detection rate and accuracy; however, its prognostic implications have not been well explored. We evaluated the overall survival and therapies received by patients undergoing varied lymph node dissection approaches for high-risk endometrial cancers. Methods Retrospective review of grade 3 endometrioid and high-grade non-endometrioid cancers at one institution over ten years. Patients who received neoadjuvant therapy and/or debulking of only grossly abnormal lymph nodes were excluded. Data was abstracted from electronic medical records. Chi-squared tests and survival analyses were used to compare groups. Results One hundred and fifty-three patients with grade 3 endometrioid, serous, clear cell, carcinosarcoma, or mixed high-grade on final pathology were identified; 16 had no lymph node dissection, 26 had sentinel lymph nodes, and 111 had complete lymph node dissection. Patients with open surgery were more likely to have complete nodes than sentinel nodes when compared to a minimally invasive approach (p<0.001). Sentinel nodal dissection significantly impacted the utilization of, or modality choice, in adjuvant therapy (p=0.051). Recurrence-free survival and cancer-specific overall survival were not significantly different across the three nodal-assessment groups. Conclusions  Sentinel lymph node dissection in high-risk endometrial cancers led to no significant differences in recurrence-free survival or cancer-specific overall survival. While limited by sample size and its retrospective nature, results from this single-institution study are hypothesis-generating and prompt consideration of non-inferiority trials. Performing the least invasive surgery possibly can lead to fewer complications while maintaining overall survival outcomes.

Can we safely forgo hysterectomy in non-fertility-sparing surgery for borderline ovarian tumors?

Forgoing hysterectomy as part of borderline ovarian tumor (BOT) staging is considered appropriate for fertility preservation. We evaluated whether forgoing hysterectomy may also be acceptable in non-fertility-sparing surgery by evaluating the frequency of uterine involvement and the rate of recurrence involving the uterus. A review of all BOTs at one institution over ten years (2009-2019) was performed. Patients with hysterectomy prior to BOT diagnosis were excluded. Data were abstracted from electronic medical records. Bivariate statistics were used to compare groups. 129 patients with BOT on final pathology were identified. 67 cases included hysterectomy. Reasons for no hysterectomy (n = 62) included fertility preservation (40), benign intraoperative frozen pathology (4), patient preference (3), comorbidities (7), and unknown (8). Four of 67 (6.0%) uterine specimens had non-invasive serosal implants, of which two had grossly visible uterine involvement and all four had grossly visible extrauterine peritoneal disease. 12 of 129 (9.3%) patients had documented recurrence, of which all had uterine preservation at the time of initial surgery. Of the 12 recurrences with uterus in situ, none were documented to involve the uterus, and all were composed of non-invasive implants. In patients with BOT grossly confined to ovaries at the time of surgery, we found no cases of uterine involvement. We found no cases in which microscopic uterine serosal involvement changed stage and no cases of recurrence involving the uterus. Hysterectomy may be able to be safely excluded from non-fertility-sparing surgery for BOTs, particularly when disease is grossly confined to the ovaries.

The Capacity of the Ovarian Cancer Tumor Microenvironment to Integrate Inflammation Signaling Conveys a Shorter Disease-free Interval.

PURPOSE: Ovarian cancer has one of the highest deaths to incidence ratios across all cancers. Initial chemotherapy is effective, but most patients develop chemoresistant disease. Mechanisms driving clinical chemo-response or -resistance are not well-understood. However, achieving optimal surgical cytoreduction improves survival, and cytoreduction is improved by neoadjuvant chemotherapy (NACT). NACT offers a window to profile pre- versus post-NACT tumors, which we used to identify chemotherapy-induced changes to the tumor microenvironment. EXPERIMENTAL DESIGN: We obtained matched pre- and post-NACT archival tumor tissues from patients with high-grade serous ovarian cancer (patient, n = 6). We measured mRNA levels of 770 genes (756 genes/14 housekeeping genes, NanoString Technologies), and performed reverse phase protein array (RPPA) on a subset of matched tumors. We examined cytokine levels in pre-NACT ascites samples (n = 39) by ELISAs. A tissue microarray with 128 annotated ovarian tumors expanded the transcriptional, RPPA, and cytokine data by multispectral IHC. RESULTS: The most upregulated gene post-NACT was IL6 (16.79-fold). RPPA data were concordant with mRNA, consistent with elevated immune infiltration. Elevated IL6 in pre-NACT ascites specimens correlated with a shorter time to recurrence. Integrating NanoString (n = 12), RPPA (n = 4), and cytokine (n = 39) studies identified an activated inflammatory signaling network and induced IL6 and IER3 (immediate early response 3) post-NACT, associated with poor chemo-response and time to recurrence. CONCLUSIONS: Multiomics profiling of ovarian tumor samples pre- and post-NACT provides unique insight into chemo-induced changes to the tumor microenvironment. We identified a novel IL6/IER3 signaling axis that may drive chemoresistance and disease recurrence.

The Stem Cell-associated Transcription Factor SOX2 as a Diagnostic Marker of High-grade Squamous Intraepithelial Lesion of the Uterine Cervix in Comparison With p16 and Ki-67.

The transcription factor SOX2 has been identified as an oncogene involved in the pathogenesis of squamous cell carcinoma (SCC) of multiple sites, including the uterine cervix. The relationship between SOX2 overexpression and the continuum of precancerous lesions of the cervix has not been previously elucidated. We evaluated SOX2 immunohistochemical expression in normal cervix, low-grade squamous intraepithelial lesion (LSIL) (mild squamous dysplasia), high-grade squamous intraepithelial lesion (HSIL) (moderate and severe dysplasia) and SCC of the cervix in comparison with p16 and Ki-67. Staining patterns were scored as negative, basal one third of the epithelium, lower two third, or full thickness. The results showed that SOX2 expression was limited to the basal one third in 84% of LSIL cases, whereas 95% of HSIL showed SOX2 expression up to two third or full thickness (P<0.0001). p16 and Ki-67 displayed similar results. The difference in SOX2 expression between moderate and severe dysplasia was not statistically significant (P=0.53). Invasive SCC positivity was as follows: SOX2 94%; p16 89%; and Ki-67 100%. Our findings support a role for SOX2 in the progression of squamous dysplasia to SCC. The Lower Anogenital Standardization Terminology Project's recent assertion of a lack of a biological correlate to cervical intraepithelial neoplasia II is also upheld by SOX2. For equivocal situations in which a diagnosis of cervical intraepithelial neoplasia II would have been made, Lower Anogenital Standardization Terminology recommends p16, or other biomarkers such as Ki-67 to clarify the diagnosis. SOX2, with a clean nuclear staining pattern, may also be suitable for this role.

Reengineering Critical Laboratory Testing for Timely Chemotherapeutic Management.

BACKGROUND: Delivery of cytotoxic therapy is a complex multifaceted process that involves harmonized collaboration between all systems involved. Optimizing laboratory turnaround time (TAT) ensures timely delivery of chemotherapy, which potentially translates into improved patient outcomes and satisfaction. In this study, we aimed to reduce the laboratory TAT for key laboratory tests to optimize the timely administration of chemotherapy. METHODS: TAT data for complete blood count (CBC) and comprehensive metabolic panel (CMP) included specimen collection to receipt (Col-Rcv), specimen receipt to result release (Rcv-Res), and the overall TAT from specimen collection to result release (Col-Res). Work flows were reconfigured to transport CBC specimens directly to the hematology laboratory after collection and to treat all CMP samples from chemotherapy clinics as urgent [i.e., shortest turnaround time (STAT)]. From the CMP, total bilirubin and creatinine-the 2 key analytes for liver and renal toxicity assessment before chemotherapy drug administration-were analyzed on ABL 800 whole blood analyzers to further improve the laboratory TAT. RESULTS: CBC showed a significant reduction in the median (Col-Res) TAT to 16 min (P < 0.0001). For CMP, by processing all specimens as STAT samples, the median (Col-Res) TAT was reduced from 74 min to 54 min (P < 0.0001), and it was further reduced to 9 min (P < 0.0001) for total bilirubin and creatinine. CONCLUSION: Careful work flow analysis and reengineering of preanalytical and analytical process for key laboratory tests significantly reduced median overall TAT to <20 min, which helped facilitate more timely delivery of chemotherapy, without necessitating the construction of a satellite laboratory.

Cutaneous Non-Neural Granular Cell Tumors Harbor Recurrent ALK Gene Fusions.

Non-neural granular cell tumor (NNGCT; also known as primitive polypoid granular cell tumor) is a rare neoplasm composed of large ovoid cells with abundant granular cytoplasm, variable nuclear pleomorphism, and the potential for regional lymph node spread. In contrast to conventional granular cell tumor (GCT), NNGCT lacks S100 expression and can exhibit greater nuclear atypia and mitotic activity. Therefore, we investigated clinicopathologic features of 12 NNGCT, and also used next-generation sequencing to identify potential driver events in a subset of NNGCT and 6 GCT. NNGCT demonstrated mild-to-moderate nuclear pleomorphism, variable mitotic activity (0 to 10/10 high-power fields), and were S100. Genetic analysis of 5 cutaneous NNGCT revealed gene fusions involving the anaplastic lymphoma kinase gene (ALK) in 3 cases (60%). Specifically, an interstitial deletion of chromosome 2 resulting in an in-frame fusion of dyanactin 1 (DCTN1) to ALK was identified in 2 cases, and a translocation resulting in a fusion between sequestosome 1 (SQSTM1) on chromosome 5 and ALK was identified in one case. Two of 6 GCT (33%) showed gains of chromosome 7. No other molecular or chromosomal alterations were detected in NNGCT and GCT. ALK immunohistochemistry revealed weak-to-moderate positivity in 4/9 cutaneous NNCGT (44%) including all 3 tumors with ALK fusions. Three oral NNGCT lacked ALK expression. NNGCT with ALK immunostaining did not have morphologic features distinguishing them from those without ALK staining. Our results demonstrate that a subset of NNGCT harbor ALK fusions, suggest that NNGCT are molecularly diverse, and further substantiate NNGCT as distinct from GCT.

PAX3 and SOX10 activate MET receptor expression in melanoma.

Melanoma is a cancer with a poorly understood molecular pathobiology. We find the transcription factors PAX3, SOX10, MITF, and the tyrosine kinase receptor MET expressed in melanoma cell lines and primary tumors. Analysis for MET expression in primary tumor specimens showed 27/40 (68%) of the samples displayed an increased expression of MET, and this expression was highly correlated with parallel expression of PAX3, SOX10, and MITF. PAX3 and MITF bind to elements in the MET promoter independently, without evidence of either synergistic activation or inhibition. SOX10 does not directly activate the MET gene alone, but can synergistically activate MET expression with either PAX3 or MITF. In melanoma cells, there was evidence of two pathways for PAX3 mediated MET induction: (i) direct activation of the gene, and (ii) indirect regulation through MITF. SK-MEL23 melanoma cells have both of these pathways intact, while SK-MEL28 melanoma cells only have the first pathway. In summary, we find that PAX3, SOX10 and MITF play an active role in melanoma cells by regulating the MET gene. In consequence, MET promotes the melanoma cancer phenotype by promoting migration, invasion, resistance to apoptosis, and tumor cell growth.