Hereditary leiomyomatosis and renal cell carcinoma syndrome associated uterine smooth muscle tumors: Bridging morphology and clinical screening.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is an autosomal dominant familial syndrome that results from germline mutation in the fumarate hydratase (FH) gene and is associated with an increased risk for smooth muscle tumors of the uterus and skin and renal cell carcinoma. HLRCC associated RCC develop in up to 25% of patients, often presenting in the fourth decade and are high stage, aggressive tumors with poor clinical outcome. Most women with HLRCC develop large and bulky uterine smooth muscle tumors (USMT) in the second to third decade, thus presenting the ideal opportunity for early detection of HLCC to enable timely implementation of surveillance for their RCC risk. However, the concept of screening women with USMT for HLRCC is challenging given that HLRCC is rare but USMT are common. In addition, FH deficiency in USMT can also result from sporadic FH gene aberrations, unrelated to HLRCC, further complicating any potential screening process. Recent studies show that tumor morphology can be used to identify FH deficiency in USMT and thereby direct patients to formal genetic counseling. The low magnification clues of staghorn shaped blood vessels and alveolar pattern should prompt for high magnification examination for eosinophilic cytoplasmic inclusions and oval nuclei containing prominent eosinophilic macronucleoli surrounded by a halo. Additional clues include Schwannoma-like growth and chain-like distribution of the tumor cells. Although immunostains exist for FH and 2SC, their role is limited in the presence of well-developed FH deficient morphology. The prevalence of germline pathogenic mutation in FH among women with USMT with FH deficient morphology is as high as 50% in some studies, with somatic FH mutation accounting for the remainder. Therefore, morphologic evaluation of USMT for features of FH deficiency can serve as a screening tool for HLRCC syndrome by triaging patients to formal hereditary risk assessment.

Corded and Hyalinized Endometrioid Adenocarcinoma (CHEC) of the Uterine Corpus are Characterized by CTNNB1 Mutations and Can Show Adverse Clinical Outcomes.

Corded and hyalinized endometrioid adenocarcinoma (CHEC) is a morphologic variant of endometrioid adenocarcinoma that is typically low-grade [International Federation of Gynecology and Obstetrics (FIGO) grade 1-2]. CHEC exhibits a biphasic appearance with gland forming adenocarcinoma merging with a diffuse component with corded growth often in a hyalinized matrix; squamous differentiation is frequent and osteoid production can be seen. This morphologic appearance can invoke a large differential diagnosis including carcinosarcoma. CHEC is thought to be associated with good clinical outcome although the available data is sparse. We performed detailed clinical, morphologic, immunohistochemical, and molecular analyses on a cohort of 7 CHEC. Six cases exhibited features of classic low-grade CHEC while one case showed greater cytologic atypia (high-grade CHEC). Patient age ranged from 19 to 69 yr. Four patients presented at stage I, 2 at stage II, and 1 at stage III. All tumors demonstrated nuclear staining for beta-catenin and loss of E-cadherin in the corded and hyalinized component. There was relative loss of epithelial markers. Loss of PTEN and ARID1A was seen in 4 and 3 tumors, respectively, and 1 tumor displayed loss of MLH1 and PMS2. Next-generation sequencing revealed CTNNB1 and PI3K pathway mutations in all 7 cases with TP53 and RB1 alterations in the high-grade CHEC. Clinical follow-up was available for 6 patients; 2 died of disease (48 and 50 mo), 2 are alive with disease (both recurred at 13 mo), and 2 have no evidence of disease (13 and 77 mo). Our study shows that CHEC universally harbors CTNNB1 mutations with nuclear staining for beta-catenin, can rarely show high-grade cytology, and can be associated with adverse clinical outcomes.

Integrated immunohistochemical and molecular analysis improves diagnosis of high-grade carcinoma in the urinary bladder of patients with prior radiation therapy for prostate cancer.

Prostatic adenocarcinoma and urothelial carcinoma typically demonstrate distinct morphologic and immunohistochemical features. However, high-grade prostate and urothelial carcinomas sometimes show significant morphologic and immunohistochemical overlap, which can result in misdiagnosis and mistreatment. This diagnostic dilemma is particularly acute in patients previously treated with radiation and/or hormone therapy for prostate cancer, who later present with high-grade carcinoma in the urinary bladder. To address the diagnostic utility of integrated immunohistochemical and molecular analysis in this setting, we evaluated 25 high-grade carcinomas of the bladder for which morphologic features were deemed indeterminate. Our analysis included immunohistochemistry for urothelial markers (GATA3, p63, uroplakin II), prostate markers (NKX3.1, prostate specific antigen, P501S), androgen receptor (AR) and ERG, along with molecular characterization using capture-based next generation DNA sequencing. Immunohistochemical findings were concordant with the final integrated diagnosis in 21 (84%) cases. However, in three (12%) cases, immunohistochemistry supported a diagnosis of urothelial carcinoma, but molecular analysis identified the correct diagnosis of prostate cancer based on the presence of a TMPRSS2-ERG fusion. One case remained unclassifiable even after this integrated analysis. Notably, in 1 of 21 cases, the presence of a TERT promoter mutation and the absence of a TMPRSS2-ERG fusion would typically favor a diagnosis of urothelial carcinoma, but the aggregate immunohistochemical and molecular findings instead supported a diagnosis of microsatellite unstable prostatic adenocarcinoma with deep deletion of MSH2 and MSH6. Our findings highlight the importance of considering prostatic origin in high-grade carcinoma of the urinary bladder of patients with a history of treated prostate cancer, even when the immunohistochemical findings favor urothelial carcinoma. In a subset of cases, an approach that integrates immunophenotypic and molecular data may help correctly assign site of origin and prevent misdiagnosis that can result from overreliance on any individual immunohistochemical or molecular result.

Multiregion exome sequencing of ovarian immature teratomas reveals 2N near-diploid genomes, paucity of somatic mutations, and extensive allelic imbalances shared across mature, immature, and disseminated components.

Immature teratoma is a subtype of malignant germ cell tumor of the ovary that occurs most commonly in the first three decades of life, frequently with bilateral ovarian disease. Despite being the second most common malignant germ cell tumor of the ovary, little is known about its genetic underpinnings. Here we performed multiregion whole-exome sequencing to interrogate the genetic zygosity, clonal relationship, DNA copy number, and mutational status of 52 pathologically distinct tumor components from ten females with ovarian immature teratomas, with bilateral tumors present in five cases and peritoneal dissemination in seven cases. We found that ovarian immature teratomas are genetically characterized by 2N near-diploid genomes with extensive loss of heterozygosity and an absence of genes harboring recurrent somatic mutations or known oncogenic variants. All components within a single ovarian tumor (immature teratoma, mature teratoma with different histologic patterns of differentiation, and yolk sac tumor) were found to harbor an identical pattern of loss of heterozygosity across the genome, indicating a shared clonal origin. In contrast, the four analyzed bilateral teratomas showed distinct patterns of zygosity changes in the right versus left sided tumors, indicating independent clonal origins. All disseminated teratoma components within the peritoneum (including gliomatosis peritonei) shared a clonal pattern of loss of heterozygosity with either the right or left primary ovarian tumor. The observed genomic loss of heterozygosity patterns indicate that diverse meiotic errors contribute to the formation of ovarian immature teratomas, with 11 out of the 15 genetically distinct clones determined to result from nondisjunction errors during meiosis I or II. Overall, these findings suggest that copy-neutral loss of heterozygosity resulting from meiotic abnormalities may be sufficient to generate ovarian immature teratomas from germ cells.

Molecular characterisation of metanephric adenomas beyond BRAF: genetic evidence for potential malignant evolution.

AIMS: Metanephric adenomas (MAs) are conventionally regarded as rare renal tumours with indolent behaviour; limited case reports have described MAs with aggressive features. Conventional MAs harbour hotspot BRAF V600E mutations. A BRAF V600E senescence pathway, mediated by cyclin-dependent kinase inhibitor 2A (CDKN2A)/p16, has been proposed to confer MA benignity. Aside from BRAF, the molecular landscape in both conventional MAs and those with aggressive features has not been fully characterised. The aim of this study was to molecularly profile a series of MAs to investigate the correlation between genomic findings and clinical outcome. METHODS AND RESULTS: We retrospectively examined the histomorphology and patient outcomes of 11 conventional MAs and one MA with aggressive features. Each was subjected to capture-based next-generation DNA sequencing of 479 cancer-related genes and immunohistochemical profiling. All tumours were positive for WT1 immunostaining and BRAF V600E mutation. One conventional MA contained an additional somatic BRCA2 pathogenic mutation. The MA with aggressive features had a biphasic appearance: one component was epithelial, with areas morphologically consistent with conventional MA; the second component was sarcomatous, with areas of solid and angiosarcomatous growth. Differential profiling of the two populations revealed identical BRAF, EIF1AX and TERT promoter hotspot mutations in the epithelial and sarcomatous components. Deep deletion of CDKN2A and MYC amplification were identified only in the sarcomatous component. CONCLUSIONS: Although the vast majority of MAs show indolent behaviour, rare pathogenic alterations can occur in conventional MAs in addition to BRAF. Molecular profiling of a case with aggressive clinical and pathological features shows genetic evidence for malignant evolution in MAs.

NTRK fusion cervical sarcoma: a report of three cases, emphasising morphological and immunohistochemical distinction from other uterine sarcomas, including adenosarcoma.

AIMS: A unique fibrosarcoma-like tumour of the uterine cervix harbouring a rearrangement of a neurotrophic tyrosine kinase receptor (NTRK) gene (NTRK1 or NTRK3) has recently been described in 11 young women, some with recurrence and/or metastasis. The aims of this study were to expand the morphological spectrum of this tumour by reporting three additional cases that showed adenosarcoma-like features not previously described, one of which is the first reported to respond to targeted therapy, and to evaluate 19 conventional uterine adenosarcomas for evidence of NTRK rearrangement. METHODS AND RESULTS: Three patients presented with a polyp or mass confined to the cervix. The constellation of polypoid growth, spindle cell morphology, entrapped endocervical glands and intraglandular stromal projections raised diagnostic consideration for adenosarcoma with stromal overgrowth. Deep cervical wall invasion was present in two cases at hysterectomy, and the third was removed by polypectomy. All three stained for S100 and pan-Trk, but were negative for a spectrum of other diagnostic markers. All three harboured NTRK rearrangements (TPM3-NTRK1, TPR-NTRK1, and SPECC1L-NTRK3). One patient developed pleural metastases at 16 months, received the NTRK inhibitor larotrectinib, and is free of disease 15 months later. Two others are alive without disease. None of the uterine adenosarcomas showed any S100 or pan-Trk staining, or rearrangement of NTRK1, NTRK2 or NTRK3 on next-generation sequencing. CONCLUSIONS: Unusual adenosarcoma-like spindle cell neoplasms of the cervix may represent an NTRK fusion sarcoma, which can be detected by S100 and pan-Trk staining and confirmed by NTRK molecular testing. Conventional uterine adenosarcomas do not harbour NTRK rearrangements.

DICER1 mutations are frequent in müllerian adenosarcomas and are independent of rhabdomyosarcomatous differentiation.

Müllerian adenosarcomas are biphasic epithelial-mesenchymal tumors with benign epithelial and malignant mesenchymal components. The sarcoma component may be low or high grade; the latter is often seen in the presence of stromal overgrowth, which correlates with worse clinical outcome. Heterologous differentiation may also occur, usually in association with stromal overgrowth. DICER1 mutations have been reported primarily in a small subset of adenosarcomas with rhabdomyosarcomatous elements, but whether these are specific to the rhabdomyosarcomatous phenotype is unclear. In this study, we examined the clinical, pathologic, and genomic features of 19 müllerian adenosarcomas enriched for tumors with rhabdomyosarcomatous differentiation, as well as eight uterine carcinosarcomas with a rhabdomyosarcoma component. Somatic hotspot mutations in the RNase IIIb domain of DICER1 were identified in 8/19 (42%) adenosarcomas, of which four showed rhabdomyosarcomatous differentiation. DICER1 mutations were detected in 4/6 (67%) cases with a rhabdomyosarcoma component and in 4/11 (36%) cases without rhabdomyosarcoma. At least two DICER1 mutations were identified in 7/8 (88%) tumors, of which four had a truncating mutation. The hotspot DICER1 mutation in the remaining tumor was hemizygous and associated with loss of heterozygosity. Other less frequent recurrent somatic pathogenic alterations included Ras or PI3K/PTEN pathway aberrations (5/19 each, 26%), CDK4/MDM2 amplifications (3/19, 16%), and mutations in TP53 (3/19) and ARID1A (3/19). Two tumors demonstrated homozygous BAP1 deletion. One tumor harbored an ESR1-NCOA3 fusion gene. Carcinosarcomas with rhabdomyosarcomatous differentiation showed frequent mutations in TP53 (7/8, 88%) and the PI3K/PTEN pathway (6/8, 75%) but lacked DICER1 mutations. The findings highlight the importance of DICER1 mutations in müllerian adenosarcoma tumorigenesis and show that these alterations are not exclusive to heterologous rhabdomyosarcomatous differentiation.

Well-differentiated papillary mesothelioma of the peritoneum is genetically defined by mutually exclusive mutations in TRAF7 and CDC42.

Well-differentiated papillary mesothelioma is an uncommon mesothelial neoplasm that most frequently arises in the peritoneal cavity of women of reproductive age. Whereas malignant mesothelioma is an aggressive tumor associated with poor outcome, well-differentiated papillary mesothelioma typically exhibits indolent behavior. However, histologically differentiating between these two entities can be challenging, necessitating the development of distinguishing biomarkers. While the genetic alterations that drive malignant mesothelioma have recently been determined, the molecular pathogenesis of well-differentiated papillary mesothelioma is unknown. Here we performed genomic profiling on a cohort of ten well-differentiated papillary mesothelioma of the peritoneum. We identified that all tumors harbored somatic missense mutations in either the TRAF7 or CDC42 genes, and lacked alterations involving BAP1, NF2, CDKN2A, DDX3X, SETD2, and ALK that are frequent in malignant mesothelioma. We recently identified that another mesothelial neoplasm, adenomatoid tumor of the genital tract, is genetically defined by somatic missense mutations in the TRAF7 gene, indicating a shared molecular pathogenesis between well-differentiated papillary mesothelioma and adenomatoid tumors. To the best of our knowledge, well-differentiated papillary mesothelioma is the first human tumor type found to harbor recurrent mutations in the CDC42 gene, which encodes a Rho family GTPase. Immunohistochemistry demonstrated intact BAP1 expression in all cases of well-differentiated papillary mesothelioma, indicating that this is a reliable marker for distinguishing well-differentiated papillary mesothelioma from malignant mesotheliomas that frequently display loss of expression. Additionally, all well-differentiated papillary mesothelioma demonstrated robust expression of L1 cell adhesion molecule (L1CAM), a marker of NF-kB pathway activation, similar to that observed in adenomatoid tumors. In contrast, we have previously shown that L1CAM staining is not observed in normal mesothelial cells and malignant mesotheliomas of the peritoneum. Together, these studies demonstrate that well-differentiated papillary mesothelioma is genetically defined by mutually exclusive mutations in TRAF7 and CDC42 that molecularly distinguish this entity from malignant mesothelioma.

Adenomatoid tumors of the male and female genital tract are defined by TRAF7 mutations that drive aberrant NF-kB pathway activation.

Adenomatoid tumors are the most common neoplasm of the epididymis, and histologically similar adenomatoid tumors also commonly arise in the uterus and fallopian tube. To investigate the molecular pathogenesis of these tumors, we performed genomic profiling on a cohort of 31 adenomatoid tumors of the male and female genital tracts. We identified that all tumors harbored somatic missense mutations in the TRAF7 gene, which encodes an E3 ubiquitin ligase belonging to the family of tumor necrosis factor receptor-associated factors (TRAFs). These mutations all clustered into one of five recurrent hotspots within the WD40 repeat domains at the C-terminus of the protein. Functional studies in vitro revealed that expression of mutant but not wild-type TRAF7 led to increased phosphorylation of nuclear factor-kappa B (NF-kB) and increased expression of L1 cell adhesion molecule (L1CAM), a marker of NF-kB pathway activation. Immunohistochemistry demonstrated robust L1CAM expression in adenomatoid tumors that was absent in normal mesothelial cells, malignant peritoneal mesotheliomas and multilocular peritoneal inclusion cysts. Together, these studies demonstrate that adenomatoid tumors of the male and female genital tract are genetically defined by TRAF7 mutation that drives aberrant NF-kB pathway activation.

Uterine Mesenchymal Tumors: Hereditary Aspects.

The topic of hereditary gynecologic malignancies readily evokes associations between Lynch syndrome and endometrial adenocarcinoma, or between BRCA mutations and tubo-ovarian serous carcinoma, but other familial associations are less well-known. Two hereditary syndromes are known to be related to uterine mesenchymal tumors: hereditary leiomyomatosis and renal cell carcinoma syndrome and the tuberous sclerosis complex. In the following review, we describe the current literature on these syndromes, summarizing their clinical, morphologic, immunophenotypic, and genetic data. It is possible that the surgical pathologic diagnosis is the first indication of a familial syndrome, thus emphasizing the importance of a pathologist's familiarity with these potentially suggestive lesions.

Genomic profiling of malignant peritoneal mesothelioma reveals recurrent alterations in epigenetic regulatory genes BAP1, SETD2, and DDX3X.

Malignant mesothelioma is a rare cancer that arises from the mesothelial cells that line the pleural cavity and less commonly from the peritoneal lining of the abdomen and pelvis. Most pleural mesotheliomas arise in patients with a history of asbestos exposure, whereas the association of peritoneal mesotheliomas with exposure to asbestos and other potential carcinogens is less clear, suggesting that the genetic alterations that drive malignant peritoneal mesothelioma may be unique from those in pleural mesothelioma. Treatment options for all malignant mesotheliomas are currently limited, with no known targeted therapies available. To better understand the molecular pathogenesis of malignant peritoneal mesothelioma, we sequenced 510 cancer-related genes in 13 patients with malignant mesothelioma arising in the peritoneal cavity. The most frequent genetic alteration was biallelic inactivation of the BAP1 gene, which occurred in 9/13 cases, with an additional two cases demonstrating monoallelic loss of BAP1. All 11 of these cases demonstrated loss of BAP1 nuclear staining by immunohistochemistry, whereas two tumors without BAP1 alteration and all 42 cases of histologic mimics in peritoneum (8 multilocular peritoneal inclusion cyst, 6 well-differentiated papillary mesothelioma of the peritoneum, 16 adenomatoid tumor, and 12 low-grade serous carcinoma of the ovary) demonstrated intact BAP1 nuclear staining. Additional recurrently mutated genes in this cohort of malignant peritoneal mesotheliomas included NF2 (3/13), SETD2 (2/13), and DDX3X (2/13). While these genes are known to be recurrently mutated in pleural mesotheliomas, the frequencies are distinct in peritoneal mesotheliomas, with nearly 85% of peritoneal tumors harboring BAP1 alterations versus only 20-30% of pleural tumors. Together, these findings demonstrate the importance of epigenetic modifiers including BAP1, SETD2, and DDX3X in mesothelial tumorigenesis and suggest opportunities for targeted therapies.

FOXL2 Mutation Status in Granulosa Theca Cell Tumors of the Ovary.

Ovarian sex-cord stromal tumors that have between 10% and 50% granulosa cells in a prominent fibrothecomatous background have been referred to as granulosa theca cell tumors or mixed granulosa theca cell tumors. The classification and prognosis of these tumors is not clear. Most adult granulosa cell tumors of the ovary harbor a mutation in the FOXL2 gene, whereas fibromas and thecomas lack this mutation. The aim of our study was to assess the FOXL2 mutation status of ovarian granulosa theca cell tumors and to correlate the mutation status with morphologic and clinical characteristics. A FOXL2 mutation was detected in 6 of 12 (50%) granulosa theca cell tumors. Tumors with higher cellularity of granulosa cells were more likely to harbor a FOXL2 mutation as were tumors in which the granulosa cells formed large lobules. No conclusions could be drawn regarding the clinical and prognostic significance of the presence of a mutation given the small number of cases and limited clinical follow-up. Our study shows that half of granulosa theca cell tumors harbor the same FOXL2 mutation that characterizes adult granulosa cell tumors but there is no outcome evidence to guide whether mutation status should alter the classification of the tumor or the management of the patient.

Interobserver Reproducibility Among Gynecologic Pathologists in Diagnosing Heterologous Osteosarcomatous Component in Gynecologic Tract Carcinosarcomas.

Distinguishing hyalinized stroma from osteoid production by a heterologous osteosarcomatous component can be challenging in gynecologic tract carcinosarcomas. As heterologous components in a carcinosarcoma may have prognostic and therapeutic implications, it is important that these are recognized. This study examines interobserver reproducibility among gynecologic pathologists in the diagnosis of osteosarcomatous components, and its correlation with expression of the novel antibody SATB2 (marker of osteoblastic differentiation) in these osteosarcomatous foci. Digital H&E images from 20 gynecologic tract carcinosarcomas were reviewed by 22 gynecologic pathologists with a request to determine the presence or absence of an osteosarcomatous component. The 20 preselected cases included areas of classic heterologous osteosarcoma (malignant cells producing osteoid; n=10) and osteosarcoma mimics (malignant cells with admixed nonosteoid matrix; n=10). Interobserver agreement was evaluated and SATB2 scored on all 20 cases and compared with the original diagnoses. Moderate agreement (Fleiss' κ=0.483) was identified for the 22 raters scoring the 20 cases with a median sensitivity of 7/10 and a median specificity of 9/10 for the diagnosis of osteosarcoma. SATB2 showed 100% sensitivity (10/10) and 60% (6/10) specificity in discriminating classic osteosarcoma from osteosarcoma mimics. Utilizing negative SATB2 as a surrogate marker to exclude osteosarcoma, 73% (16/22) of the reviewers would have downgraded at least 1 case to not contain an osteosarcomatous component (range, 1-6 cases, median 1 case). Gynecologic pathologists demonstrate only a moderate level of agreement in the diagnosis of heterologous osteosarcoma based on morphologic grounds. In such instances, a negative SATB2 staining may assist in increasing accuracy in the diagnosis of an osteosarcomatous component.

Uterine smooth muscle tumors with features suggesting fumarate hydratase aberration: detailed morphologic analysis and correlation with S-(2-succino)-cysteine immunohistochemistry.

Rare, sporadic uterine leiomyomas arise in the setting of severe metabolic aberration due to a somatic fumarate hydratase mutation. Germline mutations account for the hereditary leiomyomatosis and renal cell carcinoma syndrome, which predisposes for cutaneous and uterine leiomyomas and aggressive renal cell carcinomas. Altered fumarate hydratase leads to fumarate accumulation in affected cells with formation of S-(2-succino)-cysteine, which can be detected with the polyclonal antibody. High levels of these modified cysteine residues are found characteristically in fumarate hydratase-deficient cells but not in normal tissues or tumors unassociated with hereditary leiomyomatosis and renal cell carcinoma syndrome. We hypothesized that S-(2-succino)-cysteine-positive leiomyomas, indicating fumarate hydratase aberration, have morphologic features that differ from those without S-(2-succino)-cysteine positivity. Hematoxylin and eosin-stained slides of uterine smooth-muscle tumors were prospectively analyzed for features suggesting hereditary leiomyomatosis and renal cell carcinoma syndrome, such as prominent eosinophilic macronucleoli with perinucleolar halos, yielding nine cases. Germline genetic testing for fumarate hydratase mutations was performed in three cases. A detailed morphological analysis was undertaken, and S-(2-succino)-cysteine immunohistochemical analysis was performed with controls from a tissue microarray (leiomyomas (19), leiomyosarcomas (29), and endometrial stromal tumors (15)). Of the nine study cases, four had multiple uterine smooth muscle tumors. All cases had increased cellularity, staghorn vasculature, and fibrillary cytoplasm with pink globules. All cases had inclusion-like nucleoli with perinuclear halos (7 diffuse, 1 focal). All showed diffuse granular cytoplasmic labeling with the S-(2-succino)-cysteine antibody. Two of three tested patients had germline fumarate hydratase mutations. Only one leiomyoma from the tissue microarray controls was immunohistochemically positive, and it showed features similar to other immunohistochemically positive cases. Smooth-muscle tumors with fumarate hydratase aberration demonstrate morphological reproducibility across cases and S-(2-succino)-cysteine immuno-positivity. Although the features described are not specific for the germline fumarate hydratase mutation or the hereditary leiomyomatosis and renal cell carcinoma syndrome, their presence should suggest fumarate hydratase aberration. Identifying these cases is an important step in the diagnostic workup of patients with possible hereditary leiomyomatosis and renal cell carcinoma.

BRAF mutation is associated with early stage disease and improved outcome in patients with low-grade serous ovarian cancer.

BACKGROUND: Low-grade serous (LGS) ovarian cancer is a chemoresistant disease that accounts for 10% of serous ovarian cancers. Prior studies have reported that 28% to 35% of serous borderline (SB)/LGS ovarian tumors harbor a BRAF mutation, suggesting that BRAF inhibitors may be a rational therapeutic approach for this disease. In the current study, the authors sought to determine whether BRAF or KRAS mutation status was associated with disease stage and/or histology in patients with SB and LGS ovarian cancer. METHODS: Genetic profiles were constructed for 75 SB and LGS ovarian tumors to determine BRAF and KRAS mutation status. The incidence and identity of BRAF and KRAS mutations were defined, and the results were correlated with disease stage, response to treatment, and overall survival. RESULTS: Of 75 samples examined, 56 tumors (75%) had SB histology, and 19 tumors (25%) had LGS histology. Fifty-seven percent of tumors harbored either a KRAS mutation (n = 17) or a BRAF mutation (a valine-to-glutamate substitution at residue 600 [V600E]; n = 26). The BRAF V600E mutation was associated significantly with early disease stage (stage I/II; P < .001) and SB histology (P = .002). KRAS mutations were not associated significantly with disease stage or histology. Of the 22 patients (29%) who required chemotherapy, 20 had tumors with wild-type KRAS/BRAF, 2 had KRAS mutant tumors, and none had tumors that harbored a BRAF mutation. All patients with BRAF tumors remained alive at a median follow-up of 3.6 years (range, 1.9-129.3 months). CONCLUSIONS: V600E BRAF mutations were present in 35% of patients who had SB/LGS ovarian cancers. The presence of the BRAF V600E mutation in SB/LGS ovarian cancer was associated with early stage disease and improved prognosis. The authors concluded that patients with SB/LGS ovarian cancer who require systemic therapy are unlikely to have BRAF mutant tumors.

ZEB1 overexpression associated with E-cadherin and microRNA-200 downregulation is characteristic of undifferentiated endometrial carcinoma.

Undifferentiated endometrial carcinomas are very aggressive high-grade endometrial carcinomas that are frequently under-recognized. This study aimed to analyze the molecular alterations underlying the development of these endometrial carcinomas, focusing on those related to dedifferentiation. We assessed a series of 120 tumors: 57 grade 1 and 2 endometrioid endometrial carcinomas, 15 grade 3 endometrioid endometrial carcinomas, 27 endometrial serous carcinomas, and 21 undifferentiated endometrial carcinomas. We found a high frequency of DNA mismatch repair deficiency (38%) and moderate rate of p53 overexpression (∼33%) in undifferentiated carcinomas. In contrast to the characteristic endometrioid phenotype, there was a dramatic downregulation of E-cadherin expression in the undifferentiated subtype. Quantitative methylation studies dismissed CDH1 promoter hypermethylation as the mechanism responsible for this change in gene expression, while immunohistochemistry revealed that the E-cadherin repressor ZEB1 was frequently overexpressed (62%) in undifferentiated endometrial carcinomas. This finding was accompanied by a sharp downregulation in the expression of the miR-200 family of microRNAs, well-known targets of ZEB1. Furthermore, there was enhanced expression of epithelial-to-mesenchymal transition markers in undifferentiated endometrial carcinomas, such as N-cadherin, cytoplasmic p120, and osteonectin. In addition, HMGA2, a regulator of epithelial-to-mesenchymal transition that is expressed in aggressive endometrial tumors, such as endometrial serous carcinomas and carcinosarcomas, was expressed in >20% of undifferentiated carcinomas. These results suggest that ZEB1 overexpression, associated with E-cadherin and miR-200s downregulation, and the expression of mesenchymal markers might enhance the metastatic potential of undifferentiated endometrial carcinomas, leading to a poor prognosis. In addition, our observations suggest that the immnohistochemical analysis of E-cadherin and ZEB1 can aid in the differential diagnosis of the more agressive undifferentiated endometrial carcinomas from grade 3 endometrioid carcinomas.

Uterine Inflammatory Myofibroblastic Tumors: Proposed Risk Stratification Model Using Integrated Clinicopathologic and Molecular Analysis.

Inflammatory myofibroblastic tumor (IMT) of the uterus is a rare mesenchymal tumor with largely benign behavior; however, a small subset demonstrate aggressive behavior. While clinicopathologic features have been previously associated with aggressive behavior, these reports are based on small series, and these features are imperfect predictors of clinical behavior. IMTs are most commonly driven by ALK fusions, with additional pathogenic molecular alterations being reported only in rare examples of extrauterine IMTs. In this study, a series of 11 uterine IMTs, 5 of which demonstrated aggressive behavior, were evaluated for clinicopathologic variables and additionally subjected to capture-based next-generation sequencing with or without whole-transcriptome RNA sequencing. In the 6 IMTs without aggressive behavior, ALK fusions were the sole pathogenic alteration. In contrast, all 5 aggressive IMTs harbored pathogenic molecular alterations and numerous copy number changes in addition to ALK fusions, with the majority of the additional alterations present in the primary tumors. We combined our series with cases previously reported in the literature and performed statistical analyses to propose a novel clinicopathologic risk stratification score assigning 1 point each for: age above 45 years, size≥5 cm,≥4 mitotic figures per 10 high-power field, and infiltrative borders. No tumors with 0 points had an aggressive outcome, while 21% of tumors with 1 to 2 points and all tumors with ≥3 points had aggressive outcomes. We propose a 2-step classification model that first uses the clinicopathologic risk stratification score to identify low-risk and high-risk tumors, and recommend molecular testing to further classify intermediate-risk tumors.

HER2 IHC Expression and Gene Amplification in p53-aberrant High-grade Endometrial Endometrioid Carcinoma Suggests That This Population May Benefit From HER2 Testing and Targeted Therapy.

Among gynecologic cancers, uterine serous carcinoma (USC) has been shown to be human epidermal growth factor receptor 2 (HER2) amplified and trastuzumab has been included in the recent National Comprehensive Cancer Network (NCCN) guidelines for treatment of advanced stage or recurrent USC with HER2 overexpression/amplification. There is limited literature suggesting that a subset of high-grade endometrioid carcinomas with aberrant p53 expression may also be HER2 amplified and these patients could benefit from the addition of targeted therapy. We identified 59 p53-aberrant (mismatch repair proficient) FIGO 3 endometrioid carcinomas of the uterus. HER2 immunohistochemistry was performed in all 59 tumors and HER2 fluorescence in situ hybridization (FISH) was performed in 52 of the 59 cases. Four of the 59 cases were HER2 3+ by immunohistochemistry (6.7%), using the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) 2007, 2013, and 2018 criteria. HER2 FISH was performed in 3 of the 4 cases and was amplified in all 3. Nine, 8, and 7 tumors showed 2+ HER2 staining when applying 2018, 2013, and 2007 criteria, respectively, FISH was performed in 7 tumors and none were amplified. An additional 4 cases did not perfectly meet the 2018 ASCO/CAP criteria but were assigned a score of 2+, none were amplified by HER2 FISH. The remaining 42 cases showed 1+ or no staining for HER2, FISH was successfully performed in 38 tumors and none showed amplification. Approximately half of the tumors fulfilled criteria for HER2-low or HER2-very low (10 HER2-low and 20 HER2-very low). Our data shows that a subset of p53-aberrant high-grade endometrial endometrioid carcinoma express HER2 and these patients may benefit from the addition of targeted therapy. The role of targeted therapy in HER2-low gynecologic carcinoma is currently unexplored.

Morphologic patterns associated with BRCA1 and BRCA2 genotype in ovarian carcinoma.

This study was undertaken with the hypothesis that certain common morphologic features of ovarian carcinomas are predictably associated with BRCA1 and BRCA2 deficiencies. We selected 43 high-grade serous carcinomas diagnosed at Memorial Sloan-Kettering Cancer Center that were studied as part of The Cancer Genome Atlas pilot project. In addition to 12 randomly selected nonfamilial BRCA-unassociated cases, all 31 Memorial Sloan-Kettering Cancer Center cases with BRCA1 or BRCA2 abnormality were included (n=43). Slides were examined to assess tumor architecture, mitotic index, tumor-infiltrating lymphocytes (TILs), nuclear pleomorphism, necrosis, and involvement of fallopian tube epithelium. Comparing BRCA1-associated cases (BRCA1 germline mutation, n=4, BRCA1 somatic mutation, n=6, BRCA1 promoter methylation, n=13) with unassociated cases (n=12) identified statistically significant differences in morphology. BRCA1-associated high-grade serous carcinomas had more frequent Solid, pseudoEndometrioid, and Transitional cell carcinoma-like morphology (SET features) (P=0.0045), higher mitotic indexes (P=0.012), more TILs (P=0.034), and either geographic or comedo necrosis (P=0.034). BRCA2-associated cases (germline mutation, n=4 and somatic mutation, n=4) tended to show SET features, but they were relatively deficient in TILs and necrosis. Two algorithms incorporating tumor architecture, necrosis, and either mitotic indexes or TILs separated cases that showed 2 of 3 features (BRCA1 associated) from those with 0 of 3 features (BRCA unassociated; P=0.0016 and P=0.0033). A test set comprising 9 BRCA1 germline mutants and 14 high-grade serous carcinoma controls lacking BRCA1 and BRCA2 germline mutation was used to validate the algorithms, with specific emphasis on the ability to detect cases with BRCA1 germline mutation. Best results were obtained with the algorithm that incorporated SET features, necrosis, and mitotic index (P=0.0072; sensitivity of 1.0 (95% CI, 0.66-1.0); specificity of 0.57 (95% CI, 0.29-0.82); positive predictive value of 0.60 (95% CI, 0.32-0.84) and a negative predictive value of 1.0 (95% CI, 0.63-1.0)). These preliminary data indicate potential strong associations between morphology and genotype in high-grade serous carcinomas.