John K. Schoolmeester

Molecular characterization of mucinous ovarian tumours supports a stratified treatment approach with HER2 targeting in 19% of carcinomas

Mucinous ovarian carcinomas (MCs) typically do not respond to current conventional therapy. We have previously demonstrated amplification of HER2 in 6 of 33 (18.2%) mucinous ovarian carcinomas (MCs) and presented anecdotal evidence of response with HER2‐targeted treatment in a small series of women with recurrent HER2‐amplified (HER2+) MC. Here, we explore HER2 amplification and KRAS mutation status in an independent cohort of 189 MCs and 199 mucinous borderline ovarian tumours (MBOTs) and their association to clinicopathological features. HER2 status was assessed by immunohistochemistry (IHC), FISH, and CISH, and interpreted per ASCO/CAP guidelines, with intratumoural heterogeneity assessment on full sections, where available. KRAS mutation testing was performed with Sanger sequencing. Stage and grade were associated with recurrence on both univariate and multivariate analysis (p < 0.001). Assessment of HER2 status revealed overexpression/amplification of HER2 in 29/154 (18.8%) MCs and 11/176 (6.2%) MBOTs. There was excellent agreement between IHC, FISH, and CISH assessment of HER2 status (perfect concordance of HER2 0 or 1+ IHC with non‐amplified status, and 3+ IHC with amplified status). KRAS mutations were seen in 31/71 (43.6%) MCs and 26/33 (78.8%) MBOTs, and were near mutually exclusive of HER2 amplification. In the 189 MC cases, a total of 54 recurrences and 59 deaths (53 of progressive disease) were observed. Within MCs, either HER2 amplification/overexpression or KRAS mutation was associated with decreased likelihood of disease recurrence (p = 0.019) or death (p = 0.0041) when compared to cases with neither feature. Intratumoural heterogeneity was noted in 26% of HER2‐overexpressing cases. These data support the stratification of MCs for the testing of new treatments, with HER2‐targeted therapy as a viable option for HER2+ advanced or recurrent disease. Further research is required to delineate the molecular and clinical features of the ∼34% of MC cases with neither HER2 amplification nor KRAS mutations.

Perivascular epithelioid cell neoplasm (PEComa) of the gynecologic tract: clinicopathologic and immunohistochemical characterization of 16 cases.

Perivascular epithelioid cell tumor (PEComa) belongs to a family of tumors characterized by coexpression of melanocytic and muscle markers. Recent studies have shown that sporadic and tuberous sclerosis complex–associated PEComa may respond to mTOR inhibitors underscoring the importance of recognizing this tumor. However, its occurrence in the gynecologic tract continues to be disputed owing to its common misclassification as other types of uterine sarcoma and its controversial relationship with epithelioid smooth muscle tumors. To more fully characterize PEComa of the female genital tract, 16 cases of gynecologic PEComa were identified (1990 to 2012) and formed the basis of this study. Each case was analyzed for conventional morphologic and immunohistochemical characteristics established for PEComa of extrauterine sites; clinical outcome data were obtained for all cases. The 16 patients were aged 28 to 60 (mean 49; median 50) years, and 1 had a history of tuberous sclerosis complex. Thirteen cases were primary of the uterus, 2 of the adnexa, and 1 of the vagina. Tumor size ranged from 0.3 to 25.0 (mean 8.7) cm. Three patients died of disease, 6 were alive with disease, and 7 were alive without evidence of disease at last follow-up (1 mo to 13 y follow-up; mean 26 mo). All patients with an adverse outcome met established criteria for malignancy as proposed for extrauterine sites (ie, 2 or more features present: size ≥5 cm, high-grade nuclear features, infiltration, necrosis, lymphovascular invasion, or a mitotic rate ≥1/50 high-power fields). Of the melanocytic markers, HMB45 was most commonly expressed (16/16 positive, 100%), followed by microphthalmia transcription factor (11/12 positive, 92%), MelanA (14/16 positive, 88%), and S100 protein (2/10 positive, 20%). Of the smooth muscle markers, desmin was most commonly expressed (15/15 cases, 100%), followed by SMA (14/15 cases, 93%) and h-caldesmon (11/12 cases, 92%). TFE3 immunopositivity was identified in 5 of 13 cases; however, 3 tested cases were negative for a TFE3 rearrangement by fluorescence in situ hybridization. Current criteria for malignancy appear to be valid in the female genital tract, although modified criteria, as described herein, may be more specific. Awareness of the characteristic features of PEComa is important to help distinguish it from epithelioid smooth muscle tumors and other mimics as PEComa may respond to unique chemotherapeutic regimens.

TFE3 translocation-associated perivascular epithelioid cell neoplasm (PEComa) of the gynecologic tract: morphology, immunophenotype, differential diagnosis.

TFE3 translocation–associated PEComa is a distinct form of perivascular epithelioid cell neoplasm, the features of which are poorly defined owing to their general infrequency and limited prior reports with confirmed rearrangement or fusion. Recent investigation has found a lack of TSC gene mutation in these tumors compared with their nonrearranged counterparts, which underscores the importance of recognizing the translocated variant because of hypothetical ineffectiveness of targeted mTOR inhibitor therapy. Six cases were identified, and TFE3 rearrangement was confirmed by fluorescence in situ hybridization. Patient age ranged from 46 to 66 years (median 50 y), and none had a history of a tuberous sclerosis complex. Three cases arose in the uterine corpus, 1 in the vagina, 1 pelvic tumor, and 1 pulmonary tumor that was likely a recurrence/metastasis from a probable uterine primary. Five cases had clear cell epithelioid morphology that showed a spectrum of atypia, while 1 case had a mixture of clear cell epithelioid and spindle cells. A mostly consistent immunophenotype was observed in the clear cell epithelioid cases: each demonstrated diffuse TFE3, HMB45, cathepsinK labeling, either focal or no melanA staining, and variably weak reactivity to smooth muscle markers. The mixed clear cell epithelioid and spindle cell case had a similar expression pattern in its epithelioid component but strong muscle marker positivity in its spindle cell component. Follow-up ranged from 1 to 57 months. Three cases demonstrated aggressive behavior, and 3 cases had no evidence of recurrence. Both GYN-specific and traditional sets of criteria for malignancy were evaluated. The GYN model showed improved inclusion and specificity in comparison to the traditional model.

High-grade endometrial stromal sarcomas: a clinicopathologic study of a group of tumors with heterogenous morphologic and genetic features.

The existence of a “high-grade endometrial stromal sarcoma” category of tumors has been a controversial subject owing to, among other things, the difficulty in establishing consistent diagnostic criteria. Currently, the recommended classification for such tumors is undifferentiated uterine/endometrial sarcoma. Interest in this subject has recently increased markedly with the identification of recurrent molecular genetic abnormalities. At Mayo Clinic, a group of neoplasms has been observed that morphologically resemble, either cytologically or architecturally, classic “low-grade” endometrial stromal sarcoma but feature obvious deviations, specifically, 17 tumors with unequivocally high-grade morphology. These high-grade tumors displayed 3 morphologic themes: (1) tumors with a component that is identical to low-grade ESS that transitions abruptly into an obviously higher-grade component; (2) tumors composed exclusively of high-grade cells with uniform nuclear features but with a permeative pattern of infiltration; (3) tumors similar to the second group but with a different, yet characteristic, cytomorphology featuring enlarged round to ovoid cells (larger than those found in low-grade ESS) with smooth nuclear membranes and distinct chromatin clearing but lacking prominent nucleoli. We collected clinicopathologic data, applied immunohistochemical studies, and also tested tumors by fluorescence in situ hybridization for abnormalities in JAZF1, PHF1, YWHAE, and CCND1. Tumors from these 3 groups were found to be immunohistochemically and genetically distinct from one another. Most notable was the fact that category 3 contained all the cases that tested positive for YWHAE rearrangement, did not show any classic translocations for JAZF1, PHF1, or CCND1, often presented at a high stage, and behaved aggressively. This study demonstrates the morphologic, immunophenotypic, and molecular genetic heterogeneity that exists within “undifferentiated endometrial sarcomas” as currently defined and lends credence to the effort of subclassifying some tumors as truly “high-grade endometrial stromal sarcomas.” Our study also shows that, in the context of undifferentiated endometrial sarcomas, recognition of cytomorphologic features on routine hematoxylin and eosin–stained sections may be used to select tumors with specific molecular genetic changes—that is, translocations involving YWHAE. Our conclusions will help further efforts towards proper sub-classification of these tumors which will aid in diagnosis and potentially affect clinical management.

A Novel Role of the Sp/KLF Transcription Factor KLF11 in Arresting Progression of Endometriosis

Endometriosis affects approximately 10% of young, reproductive-aged women. Disease associated pelvic pain; infertility and sexual dysfunction have a significant adverse clinical, social and financial impact. As precise disease etiology has remained elusive, current therapeutic strategies are empiric, unfocused and often unsatisfactory. Lack of a suitable genetic model has impaired further translational research in the field. In this study, we evaluated the role of the Sp/KLF transcription factor KLF11/Klf11 in the pathogenesis of endometriosis. KLF11, a human disease-associated gene is etiologically implicated in diabetes, uterine fibroids and cancer. We found that KLF11 expression was diminished in human endometriosis implants and further investigated its pathogenic role in Klf11-/- knockout mice with surgically induced endometriotic lesions. Lesions in Klf11-/- animals were large and associated with prolific fibrotic adhesions resembling advanced human disease in contrast to wildtype controls. To determine phenotype-specificity, endometriosis was also generated in Klf9-/- animals. Unlike in Klf11-/- mice, lesions in Klf9-/- animals were neither large, nor associated with a significant fibrotic response. KLF11 also bound to specific elements located in the promoter regions of key fibrosis-related genes from the Collagen, MMP and TGF-β families in endometrial stromal cells. KLF11 binding resulted in transcriptional repression of these genes. In summary, we identify a novel pathogenic role for KLF11 in preventing de novo disease-associated fibrosis in endometriosis. Our model validates in vivo the phenotypic consequences of dysregulated Klf11 signaling. Additionally, it provides a robust means not only for further detailed mechanistic investigation but also the ability to test any emergent translational ramifications thereof, so as to expand the scope and capability for treatment of endometriosis.

Myxoid Leiomyosarcoma of the Uterus: A Clinicopathologic Analysis of 30 Cases and Review of the Literature With Reappraisal of Its Distinction From Other Uterine Myxoid Mesenchymal Neoplasms.

Myxoid leiomyosarcoma (mLMS) of the uterus is a rare neoplasm; thus, knowledge of its clinical behavior and morphology remains limited. We therefore reviewed 30 cases initially diagnosed as uterine mLMS to better characterize its clinicopathologic features. Diagnosis was confirmed in 25 subjects (average age 51.5 y), of whom 80% were stage 1 at presentation. The average tumor size was 10.8 cm. An infiltrative tumor border was observed microscopically in 24 cases (96%); the border in 1 case could not be assessed. Fourteen cases (56%) had >10 mitoses per 10 high-power fields, 8 (32%) had between 2 and 10, and 3 cases (12%) had <2 mitoses. Geographic tumor necrosis and moderate to severe nuclear pleomorphism were seen concurrently in 12 cases (48%). All tumors expressed smooth muscle markers. Estrogen receptor was expressed in 29.4% of cases. Eighteen of 21 cases (85.7%) were negative for ALK by immunohistochemistry. Follow-up information was available in 18 subjects: 8 died of disease, 6 were alive with local and/or distant recurrence, and 4 were alive with no evidence of disease. Individuals who died of disease tended to have tumors with >10 mitoses per 10 high-power fields. Among cases with ≥5-year follow-up, overall survival was 11.1%, significantly worse compared with reported survival rates for conventional LMS. The initial diagnosis of mLMS was revised in 5 cases. Four had a distinctive loose myxoid appearance, nuclei with vesicular chromatin, and ALK positivity by immunohistochemistry, suggesting, suggesting inflammatory myofibroblastic tumor. This diagnosis was confirmed by in situ hybridization in 2 cases. One additional myxoid tumor lacked smooth muscle or myofibroblastic features and could not be classified further. mLMS is an aggressive neoplasm characterized by infiltrative tumor borders and variability of other features (mitotic count, atypia, and necrosis). The differential diagnosis includes myxoid leiomyoma and inflammatory myofibroblastic tumor. Attention to distinguishing morphologic features and immunohistochemistry will aid in the interpretation. An illustrated algorithm with criteria for diagnosis is proposed.

Synovial sarcoma of the kidney: a clinicopathologic, immunohistochemical, and molecular genetic study of 16 cases.

We report the clinicopathologic and immunohistochemical features of 16 cases of genetically confirmed primary synovial sarcoma of the kidney. The cases occurred in 9 men and 7 women ranging in age from 17 to 78 years (mean, 46 y). The tumors were grossly large, solid, and variably cystic (2.2 to 19.0 cm; mean 8.6 cm). Microscopically, all tumors were of the monophasic type and diffusely immunoreactive for TLE1 and BCL-2. Focal pankeratin positivity was found in just under half. Ten cases carried an SS18-SSX2 fusion transcript, and 5 cases showed an SS18-SSX1 transcript by reverse transcription polymerase chain reaction. The remaining case demonstrated SS18 rearrangement by fluorescence in situ hybridization. Clinical follow-up information was available for 12 patients (range, 1 to 77 mo; mean, 32.5 mo). Fourteen patients underwent radical nephrectomy, and 3 patients had lung metastases at presentation. Six patients died of disease within 1 to 58 months (mean, 31 mo) of their diagnosis. Five patients were alive without evidence of disease 12 to 77 months (mean, 39 mos) after surgery. A single patient was alive with metastases to the spine 11 months after surgery. We conclude that renal synovial sarcoma is an aggressive tumor, with adverse patient outcome in >50% of cases. Synovial sarcoma must be distinguished from morphologically similar lesions of the kidney.

Epigenetic Regulation of Uterine Biology by Transcription Factor KLF11 via Posttranslational Histone Deacetylation of Cytochrome p450 Metabolic Enzymes

Endocrine regulation of uterine biology is critical for embryo receptivity and human reproduction. Uterine endometrium depends on extrinsic sex steroid input and hence likely has mechanisms that enable adaptation to hormonal variation. Emerging evidence suggests that sex steroid bioavailability in the endometrium is determined by adjusting their metabolic rate and fate via regulation of cytochrome (CYP) p450 enzymes. The CYP enzymes are targeted by ubiquitously expressed Sp/Krüppel-like (Sp/KLF) transcription factors. Specifically, KLF11 is highly expressed in reproductive tissues, regulates an array of endocrine/metabolic pathways via epigenetic histone-based mechanisms and, when aberrantly expressed, is associated with diabetes and reproductive tract diseases, such as leiomyoma and endometriosis. Using KLF11 as a model to investigate epigenetic regulation of endometrial first-pass metabolism, we evaluated the expression of a comprehensive array of metabolic enzymes in Ishikawa cells. KLF11 repressed most endometrial CYP enzymes. To characterize KLF11-recruited epigenetic regulatory mechanisms, we focused on the estrogen-metabolizing enzyme CYP3A4. KLF11 expression declined in secretory phase endometrial epithelium associated with increased CYP3A4 expression. Additionally, KLF11 bound to CYP3A4 promoter GC elements and thereby repressed promoter, message, protein as well as enzymatic function. This repression was epigenetically mediated, because KLF11 colocalized with and recruited the corepressor SIN3A/histone deacetylase resulting in selective deacetylation of the CYP3A4 promoter. Repression was reversed by a mutation in KLF11 that abrogated cofactor recruitment and binding. This repression was also pharmacologically reversible with an histone deacetylase inhibitor. Pharmacological alteration of endometrial metabolism could have long-term translational implications on human reproduction and uterine disease.

Invasive Stratified Mucin-producing Carcinoma and Stratified Mucin-producing Intraepithelial Lesion (SMILE): 15 Cases Presenting a Spectrum of Cervical Neoplasia With Description of a Distinctive Variant of Invasive Adenocarcinoma.

Stratified mucin-producing intraepithelial lesion (SMILE) is a cervical intraepithelial lesion, distinct from conventional squamous or glandular counterparts, believed to arise from embryonic cells at the transformation zone by transdifferentiation during high-risk HPV-associated carcinogenesis. It is characterized by stratified, immature epithelial cells displaying varying quantities of intracytoplasmic mucin throughout the majority of the lesional epithelium. We identified a distinct form of invasive cervical carcinoma with morphologic features identical to those in SMILE, which we have termed “invasive stratified mucin-producing carcinoma.” Fifteen cases from 15 patients (mean 36 y; range, 22 to 64 y) were retrieved from the pathology archives of multiple institutions with a diagnosis of either SMILE or invasive cervical carcinoma with a description or comment about the invasive tumor’s resemblance to SMILE. Seven cases had solely intraepithelial disease with a component of SMILE (mean 29 y; range, 22 to 40 y). The 8 other cases had invasive stratified mucin-producing carcinoma (mean 44; range, 34 to 64 y) in which SMILE was identified in 7. All cases of invasive stratified mucin-producing carcinoma demonstrated stratified, immature nuclei with intracytoplasmic mucin, which morphologically varied between cases from “mucin-rich” to “mucin-poor” in a similar manner to SMILE. All cases had mitotic figures and apoptotic debris, and an intralesional neutrophilic infiltrate was seen in the majority of cases. In cases of invasive carcinoma, the depth of invasion ranged from <1 to 19 mm. Follow-up information was available in 8 cases and ranged from 1 to 36 months (mean 11 mo). Three cases of invasive stratified mucin-producing carcinoma had biopsy or resection-proven metastatic carcinoma on follow-up. These 15 cases of cervical stratified mucin-producing lesions show a combination of intraepithelial and invasive growth patterns. Given that SMILE is well rooted as a distinct intraepithelial lesion, we propose “invasive stratified mucin-producing carcinoma” to describe its corresponding form of invasive carcinoma.

SMARCB1-deficient Vulvar Neoplasms: A Clinicopathologic, Immunohistochemical, and Molecular Genetic Study of 14 Cases.

Loss of expression of the SMARCB1 (INI1/BAF47/SNF5) tumor-suppressor protein, originally identified in pediatric malignant rhabdoid tumors, has been noted in significant percentages of epithelioid sarcomas of classical and proximal-type and in myoepithelial carcinomas. Epithelioid sarcoma and myoepithelial carcinoma are very rare in the vulvar region, and few of these cases have been evaluated for SMARCB1 protein loss by immunohistochemistry (IHC) or for SMARCB1 gene alterations by molecular genetic techniques. We studied the clinicopathologic, IHC, and molecular genetic features of 14 SMARCB1-deficient vulvar neoplasms. All available routinely stained sections were reexamined, and IHC analysis for wide-spectrum cytokeratins, high–molecular weight cytokeratins, epithelial membrane antigen, S100 protein, CD34, smooth muscle actin, desmin, and SMARCB1 was performed. Multiplex ligation-dependent probe amplification and DNA sequencing of the SMARCB1 gene was performed on 12 cases with sufficient available tissue. The 14 vulvar tumors occurred in adult women (mean age 46 y, range 22 to 62 y) and measured 1.1 to 8.8 cm in size (mean 4.7 cm). Tumors were classified as classical-type epithelioid sarcoma (N=1), proximal-type epithelioid sarcoma (N=6), myoepithelial carcinoma (N=4), and “SMARCB1-deficient vulvar sarcoma, not otherwise specified” (N=3) on the basis of combined histopathologic and IHC findings. One myoepithelial carcinoma showed divergent rhabdomyoblastic differentiation. All tested cases showed partial or complete SMARCB1 deletions (homozygous: 9 cases; heterozygous: 3 cases). One case with a heterozygous deletion also showed a c.528delC mutation in exon 5. Fluorescence in situ hybridization for EWSR1 rearrangement was performed for 3 cases classified as myoepithelial carcinoma and was negative. Follow-up (13 patients, range 5 to 72 mo, mean 31 mo) data showed 3 patients dead of disease, 1 alive with unresectable metastatic disease, 1 alive with radiographic evidence of extensive lymph nodal disease, and 8 alive without disease. We conclude that SMARCB1-deficient vulvar neoplasms chiefly comprise epithelioid sarcoma and myoepithelial carcinoma, although some defy easy classification. No association was seen between clinical behavior and the type of SMARCB1 alteration.