Karuna Garg

Selection of endometrial carcinomas for DNA mismatch repair protein immunohistochemistry using patient age and tumor morphology enhances detection of mismatch repair abnormalities.

Women with hereditary nonpolyposis colorectal cancer (HNPCC) have a high risk for endometrial cancer (EC) and frequently present with a gynecologic cancer as their first or sentinel malignancy. Identification of these patients is important given their personal and family risk for synchronous and metachronous tumors. The revised Bethesda Guidelines provide screening criteria for HNPCC in colorectal cancers. However, there are currently no such screening recommendations for women with endometrial carcinoma. We applied some of the colorectal cancer screening criteria, including age and tumor morphology, to endometrial endometrioid carcinoma. The purpose of this study was to describe patient and tumor characteristics and to assess the ability of these criteria to enhance detection of mismatch repair (MMR) deficiency, and hence HNPCC in EC. Immunohistochemistry (IHC) for DNA mismatch repair (IHC-MMR) proteins was performed in a defined subset of patients with EC. This included women younger than 50 years of age and women ≥50 years whose tumors showed morphologic features suggestive of MMR deficiency (TM-MMR). The extent of IHC-MMR in the older patient group was compared with that in a comparison group of EC ≥50 years that was previously analyzed for microsatellite instability status. Seventy-one patients met the selection criteria for IHC testing; 32 (45%) showed abnormal results. The rate of IHC abnormality in the younger group was approximately 30% with a nearly equal distribution of MLH1/PMS2 and MSH2/MSH6 abnormalities. In the older age group, TM-MMR triggered IHC analysis in 31 of 34 cases. Of these, 18 cases showed loss of IHC-MMR (58% of cases), 7 with loss of MSH2/MSH6. In contrast, the rate of microsatellite instability in the comparison group was only 21%. The IHC abnormal group showed more frequent tumor infiltrating lymphocytes, dedifferentiated EC, more tumors centered in the lower uterine segment, and more frequent synchronous clear cell carcinomas of the ovary than tumors with a normal immunophenotype. Although many of the patients with loss of IHC-MMR showed personal and/or family history (13 of 32) of HNPCC-associated tumors, most did not. Tumor morphology (TM-MMR) along with IHC-MMR enhances the detection of EC patients at risk of HNPCC.

Endometrial and ovarian carcinomas with undifferentiated components: clinically aggressive and frequently underrecognized neoplasms

Carcinomas of the endometrium and ovary with undifferentiated components are uncommon neoplasms that are likely underdiagnosed. They are important to recognize as they have been shown to be clinically aggressive. We identified 32 carcinomas with undifferentiated components as defined by Silva and co-workers, 26 endometrial and 6 of ovarian origin. The patient age ranged from 21 to 76 years (median 55); 40% of patients were ≤50 years of age. Most patients (58% of endometrial and 83% of ovarian carcinomas with undifferentiated components) presented at advanced stages (FIGO III–IV). Pelvic and para-aortic lymph nodes were the most frequent sites of metastases. Twenty tumors, entirely undifferentiated, consisted of sheets of dyshesive, ovoid cells with uniform, large vesicular nuclei, whereas 12 tumors contained combinations of differentiated endometrioid adenocarcinoma with undifferentiated components. Although most undifferentiated tumors had a monotonous cytologic appearance without prominent stroma, six showed focal nuclear pleomorphism and eight cases had variably sized zones of rhabdoid cells in a background of myxoid stroma. The tumors were frequently misdiagnosed; they received a wide range of diagnoses, including FIGO grade 2 or 3 endometrioid carcinoma, carcinosarcoma, high-grade sarcoma including endometrial stromal sarcoma, neuroendocrine carcinoma, lymphoma, granulosa cell tumor and epithelioid sarcoma. Up to 86% of the cases showed focal, but strong keratin and/or epithelial membrane antigen staining, with CK18 being the most frequently positive keratin stain. They were predominantly negative for neuroendocrine markers, smooth muscle markers and estrogen receptor/progesterone receptor. Mismatch repair protein expression by immunohistochemistry was evaluated in 17 cases, and 8 (47%) were abnormal (7 with loss of MLH1/PMS2 and 1 with MSH6 loss). Follow-up was available for 27 patients, although it was very short in many cases, ranging from 0.5 to 89 months (median 9 months). Eleven patients (41%) died of the disease in 0.5–20 months, four are alive with disease and twelve patients have no evidence of disease. Endometrial and ovarian carcinomas with undifferentiated components have a broad histologic differential diagnosis, but they show specific histologic features that should enable accurate diagnosis. These tumors can occur in young women, may be associated with microsatellite instability and behave in a clinically aggressive manner.

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

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.

Lynch syndrome (hereditary non-polyposis colorectal cancer) and endometrial carcinoma

Women with hereditary non-polyposis colorectal cancer (HNPCC)/Lynch syndrome have a high risk for endometrial cancer (EC) and frequently present with a gynaecological cancer as their first or sentinel malignancy. Identification of these patients is important given their personal and family risk for synchronous and metachronous tumours. Modalities to detect ECs for the possibility of HNPCC include microsatellite instability assay, immunohistochemistry for DNA mismatch repair proteins, MLH1 promoter hypermethylation assay and mutational analysis of DNA mismatch repair genes. The revised Bethesda guidelines provide screening criteria for HNPCC in colorectal cancers (CRCs). However, there are currently no such screening recommendations for women with endometrial carcinoma. While age and family history are useful screening criteria, their sensitivity has been shown to be low for detection of HNPCC in EC. Expansion of these criteria to include tumour morphology (presence of tumour infiltrating lymphocytes and tumour heterogeneity including dedifferentiated/undifferentiated ECs) and topography (lower uterine segment localisation) as well as presence of synchronous ovarian clear cell carcinomas may significantly enhance the detection of patients with EC at risk for HNPCC. Consideration should be given to incorporating these screening criteria into a revision of the Bethesda guidelines for detecting EC patients at highest risk for HNPCC.

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.

Endometrial carcinomas in women aged 40 years and younger: tumors associated with loss of DNA mismatch repair proteins comprise a distinct clinicopathologic subset.

Endometrial carcinomas (ECs) in young women (≤40 y) are usually managed conservatively in selected patients. Whether oophorectomy with total hysterectomy is mandated for patients failing hormonal therapy is controversial. Recognition of features that might discourage conservative management and ovarian preservation are currently poorly characterized. We evaluated these patients for DNA mismatch repair (MMR) protein defects to assess whether the MMR status had an impact on therapeutic decision making. Seventy ECs in women of 40 years of age or younger (n=70) were identified from review of institutional databases (1993—present). All available slides were reviewed and DNA MMR immunohistochemistry was performed using 4 markers (MLH1, PMS2, MSH2, and MSH6) in cases with available blocks (n=54). ECs were predominantly endometrioid (65/70), and most were low grade (1988 International Federation of Gynecology and Obstetrics grades 1 or 2, 83%). Five (7%) were undifferentiated carcinomas. Most patients presented at early stage (stages I to II, 90%). A significant number of patients also had synchronous ovarian carcinomas (9 of 70, 13%), predominantly endometrioid (7 of 9), whereas 2 were ovarian clear cell carcinomas. Sixty-six of the 70 patients are alive with no evidence of disease, whereas 4 patients (6%) died of disease. Immunohistochemistry for DNA MMR showed loss of at least 1 protein in 9 of 54 cases (16%) with slight predominance of MSH2/MSH6 abnormalities (5 of 9) compared with loss of MLH1/PMS2. Tumors with MMR loss frequently occurred in women with low body mass index; these tumors were of higher grade and associated with worse clinical outcomes. They frequently showed tumor characteristics associated with microsatellite instability, including tumor infiltrating lymphocytes, undifferentiated or dedifferentiated histology, and lower uterine segment origin. These tumors also showed lower estrogen receptor/progesterone receptor expression compared with tumors with retained staining for MMR proteins. None of the cases with synchronous ovarian and endometrial endometrioid carcinomas showed loss of MMR proteins, whereas 1 of 2 ECs with synchronous CCC of ovary showed loss of MSH2/MSH6. As young women with endometrioid carcinomas who show loss of mismatch proteins are at risk for high-grade tumors with worse clinical outcomes and lower estrogen receptor/progesterone receptor expression, they may not be appropriate candidates for conservative management. Although young EC patients are at increased risk for synchronous endometrioid ovarian carcinomas, this does not seem to be associated with MMR loss.

Early detection of high-grade tubal serous carcinoma in women at low risk for hereditary breast and ovarian cancer syndrome by systematic examination of fallopian tubes incidentally removed during benign surgery.

Early detection of sporadic pelvic serous carcinoma remains an elusive goal. In women at high risk for hereditary breast and ovarian cancer syndrome who undergo prophylactic salpingectomy, systematic pathologic examination of the fallopian tubes will detect occult tubal cancer, mostly in the fimbriae, of a minority of women. Such tubal cancers are the putative precursor to advanced-stage pelvic cancer. We hypothesized that early tubal cancer detection can also be accomplished in women at low risk using a similar approach. In this study, we performed complete and systematic examination of the fallopian tubes removed during surgery performed for benign indications. Among 522 women, 4 cases of serous tubal intraepithelial carcinoma (STIC) were identified. Three of these cases would have gone undetected using the current standard of care of sampling only a single random section of the tube. The fourth case was accompanied by occult ovarian carcinoma. The fimbriae contained STIC in 3 of the 4 cases and atypical mucosa in 1 case in which the STIC was in the nonfimbriated portion of the tube. The morphologic and immunohistochemical features (aberrant p53 and MIB-1) of these STICs were similar to those expected in high-risk women. All 4 patients with STIC underwent BRCA1 and BRCA2 gene testing; no germline mutations were identified in any patient. An additional 11 specimens contained atypical mucosal proliferations that fell short of morphologic and immunohistochemical criteria for STIC. Two of these 11 fulfilled criteria for a serous tubal intraepithelial lesion, and the remaining atypical proliferations exhibited normal p53 and MIB-1. For most specimens, the fimbriae could be completely submitted in 1 or 2 cassettes per tube. These results demonstrate that systematic examination of the tubal fimbriae can serve as a form of early detection of sporadic tubal cancer without incurring significant labor or cost. We propose that the tubal fimbriae should be completely examined in all patients undergoing benign surgery even if there are no clinical features to suggest risk for hereditary breast and ovarian cancer syndrome.

p53 overexpression in morphologically ambiguous endometrial carcinomas correlates with adverse clinical outcomes

The distinction between uterine serous and endometrioid carcinomas can usually be achieved by morphologic examination alone. However, there are occasional ‘morphologically ambiguous endometrial carcinomas’ that show overlapping serous and endometrioid features and defy histologic classification. The primary aim of this study was to assess the clinical significance of p53 overexpression using immunohistochemistry in such tumors. Related aims included (1) assessing interobserver diagnostic concordance for histologic subclassification of these tumors using a panel of pathologists with and without gynecologic pathology expertise and (2) elucidating the histologic features that correlate with p53 status. Thirty-five such cases were identified during the study period. p53 overexpression was seen in 17 of 35 cases. Tumors with p53 overexpression were associated with a significantly inferior progression-free survival and disease-specific survival compared with those that lacked p53 overexpression (3-year progression-free survival and disease-specific survival were 94 and 100% in patients with no p53 overexpression, and 52 and 54% in patients with p53 overexpression; P=0.02 and 0.003, respectively). The consensus diagnosis rendered by gynecologic pathologists was predictive of disease-specific survival (P=0.002), but not progression-free survival (P=0.11). Although the interobserver diagnostic concordance (kappa=0.70) was substantial for gynecologic pathologists, and highly associated with p53 status (77% of ‘favor serous’ cases showed p53 overexpression, whereas only 25% of ‘favor endometrioid’ cases showed p53 overexpression; P=0.005), the concordance between the consensus diagnosis of the two specialized pathologists versus each of three non-specialized pathologists was poor (kappa=0.13–0.25). The histologic feature that correlated most with p53 overexpression was the presence of diffuse high nuclear grade. p53 immunohistochemistry assays in morphologically ambiguous endometrial carcinomas are roughly as clinically informative as gynecologic pathology consultation and can be helpful for prognostic assessment and therapeutic decision making in difficult endometrial carcinomas.

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.

Pathologic scoring of PTEN immunohistochemistry in endometrial carcinoma is highly reproducible

Endometrial carcinomas show frequent PTEN-PI3K pathway abnormalities, and there are currently multiple trials focused on PI3K pathway inhibitors in patients with endometrial carcinoma. PTEN immunohistochemistry may help to select patients with potential for response to targeted therapy, making it important to develop and validate this stain in formalin-fixed, paraffin-embedded tissue. Immunohistochemistry for PTEN was performed and scored independently on 118 cases of endometrial carcinomas from 2 cancer centers using monoclonal DAKO 6H2.1 antibody. Cases were scored as positive, negative, or heterogeneous; reproducibility of PTEN staining and interpretation was assessed. Overall interobserver agreement was good (weighted &kgr;=0.80), with 82% concordance, similar for nonendometrioid (81%) and endometrioid carcinomas (85%). Twenty-one of 118 cases showed discrepant results (17%) that resulted from differences in interpretation and not staining. Our study shows that evaluation of PTEN loss by immunohistochemistry is highly reproducible with the application of standard immunohistochemical techniques and simple scoring criteria.