A Common Variant at the 14q32 Endometrial Cancer Risk Locus Activates AKT1 through YY1 Binding.

A recent meta-analysis of multiple genome-wide association and follow-up endometrial cancer case-control datasets identified a novel genetic risk locus for this disease at chromosome 14q32.33. To prioritize the functional SNP(s) and target gene(s) at this locus, we employed an in silico fine-mapping approach using genotyped and imputed SNP data for 6,608 endometrial cancer cases and 37,925 controls of European ancestry. Association and functional analyses provide evidence that the best candidate causal SNP is rs2494737. Multiple experimental analyses show that SNP rs2494737 maps to a silencer element located within AKT1, a member of the PI3K/AKT/MTOR intracellular signaling pathway activated in endometrial tumors. The rs2494737 risk A allele creates a YY1 transcription factor-binding site and abrogates the silencer activity in luciferase assays, an effect mimicked by transfection of YY1 siRNA. Our findings suggest YY1 is a positive regulator of AKT1, mediating the stimulatory effects of rs2494737 increasing endometrial cancer risk. Identification of an endometrial cancer risk allele within a member of the PI3K/AKT signaling pathway, more commonly activated in tumors by somatic alterations, raises the possibility that well tolerated inhibitors targeting this pathway could be candidates for evaluation as chemopreventive agents in individuals at high risk of developing endometrial cancer.

Blocking 17ß-hydroxysteroid dehydrogenase type 1 in endometrial cancer: a potential novel endocrine therapeutic approach.

The enzyme type 1 17ß-hydroxysteroid dehydrogenase (17ß-HSD-1), responsible for generating active 17ß-estradiol (E2) from low-active estrone (E1), is overexpressed in endometrial cancer (EC), thus implicating an increased intra-tissue generation of E2 in this estrogen-dependent condition. In this study, we explored the possibility of inhibiting 17ß-HSD-1 and impairing the generation of E2 from E1 in EC using in vitro, in vivo, and ex vivo models. We generated EC cell lines derived from the well-differentiated endometrial adenocarcinoma Ishikawa cell line and expressing levels of 17ß-HSD-1 similar to human tissues. In these cells, HPLC analysis showed that 17ß-HSD-1 activity could be blocked by a specific 17ß-HSD-1 inhibitor. In vitro, E1 administration elicited colony formation similar to E2, and this was impaired by 17ß-HSD-1 inhibition. In vivo, tumors grafted on the chicken chorioallantoic membrane (CAM) demonstrated that E1 upregulated the expression of the estrogen responsive cyclin A similar to E2, which was impaired by 17ß-HSD-1 inhibition. Neither in vitro nor in vivo effects of E1 were observed using 17ß-HSD-1-negative cells (negative control). Using a patient cohort of 52 primary ECs, we demonstrated the presence of 17ß-HSD-1 enzyme activity (ex vivo in tumor tissues, as measured by HPLC), which was inhibited by over 90% in more than 45% of ECs using the 17ß-HSD-1 inhibitor. Since drug treatment is generally indicated for metastatic/recurrent and not primary tumor, we next demonstrated the mRNA expression of the potential drug target, 17ß-HSD-1, in metastatic lesions using a second cohort of 37 EC patients. In conclusion, 17ß-HSD-1 inhibition efficiently blocks the generation of E2 from E1 using various EC models. Further preclinical investigations and 17ß-HSD-1 inhibitor development to make candidate compounds suitable for the first human studies are awaited. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

White Blood Cell BRCA1 Promoter Methylation Status and Ovarian Cancer Risk.

Background: The role of normal tissue gene promoter methylation in cancer risk is poorly understood. Objective: To assess associations between normal tissue BRCA1 methylation and ovarian cancer risk. Design: 2 case-control (initial and validation) studies. Setting: 2 hospitals in Norway (patients) and a population-based study (control participants). Participants: 934 patients and 1698 control participants in the initial study; 607 patients and 1984 control participants in the validation study. Measurements: All patients had their blood sampled before chemotherapy. White blood cell (WBC) BRCA1 promoter methylation was determined by using methylation-specific quantitative polymerase chain reaction, and the percentage of methylation-positive samples was compared between population control participants and patients with ovarian cancer, including the subgroup with high-grade serous ovarian cancer (HGSOC). Results: In the initial study, BRCA1 methylation was more frequent in patients with ovarian cancer than control participants (6.4% vs. 4.2%; age-adjusted odds ratio [OR], 1.83 [95% CI, 1.27 to 2.63]). Elevated methylation, however, was restricted to patients with HGSOC (9.6%; OR, 2.91 [CI, 1.85 to 4.56]), in contrast to 5.1% and 4.0% of patients with nonserous and low-grade serous ovarian cancer (LGSOC), respectively. These findings were replicated in the validation study (methylation-positive status in 9.1% of patients with HGSOC vs. 4.3% of control participants-OR, 2.22 [CI 1.40 to 3.52]-4.1% of patients with nonserous ovarian cancer, and 2.7% of those with LGSOC). The results were not influenced by tumor burden, storage time, or WBC subfractions. In separate analyses of young women and newborns, BRCA1 methylation was detected in 4.1% (CI, 1.8% to 6.4%) and 7.0% (CI, 5.0% to 9.1%), respectively. Limitations: Patients with ovarian cancer were recruited at the time of diagnosis in a hospital setting. Conclusion: Constitutively normal tissue BRCA1 promoter methylation is positively associated with risk for HGSOC. Primary Funding Source: Norwegian Cancer Society.

HER2 expression patterns in paired primary and metastatic endometrial cancer lesions.

BACKGROUND: Despite successful implementation of drugs targeting the human epidermal growth factor receptor 2 (HER2) receptor in breast and gastric cancers, the potential of HER2 as a therapeutic target in other cancers has been less studied, including endometrial cancer. We investigated expression levels of HER2 (ERBB2) in a large cohort of endometrial cancer lesions, also including complex atypical hyperplasia and metastatic lesions. METHODS: 67 precursor lesions, 790 primary endometrial cancers and 383 metastatic lesions were investigated for HER2 expression in relation to clinicopathologic features and outcome. Protein levels were assessed by immunohistochemistry (using the HercepTest and staining index (SI) criteria), mRNA levels by microarrays and amplification status by chromogenic in situ hybridisation. RESULTS: High HER2 protein levels were significantly associated with features of aggressive disease and increased mRNA ERBB2 levels. HER2 expression defined by the SI proved to be a better predictor of survival compared with the HercepTest. A discordant HER2 expression pattern between paired primary and metastatic lesions was detected, revealing substantial reduction in HER2 expression from primary to metastatic disease. CONCLUSIONS: Loss of HER2 expression is common in metastatic endometrial cancer lesions and assessment of HER2 levels in the metastatic lesions may be important to define the potential benefit of anti-HER2 treatments in endometrial cancer patients.

The genetic landscape of 87 ovarian germ cell tumors.

BACKGROUND: Ovarian germ cell tumors (OGCT) are rare gynecological neoplasms, mostly affecting children and young women. The underlying molecular genetic background of these tumors is poorly characterized. METHODS: We analyzed somatic copy number aberration (CNA) profiles in 87 OGCT tumors and performed whole exome sequencing (WES) on 24 OGCT tumor and matched germline samples to further elucidate their molecular genetic landscape. RESULTS: The overall mutation rate was very low in OGCT compared to other human cancers, with an average of 0.05 mutations per Mb, consistent with their embryological origin. We identified recurrent mutations in KIT and KRAS, while CNA profiling revealed frequent focal amplifications affecting PIK3CA and AKT1 in yolk sac tumors, recurrent focal deletions affecting chromosomal regions 1p36.32, 2q11.1, 4q28.1, 5p15.33, 5q11.1 and 6q27, as well as gains in chromosome 12p that were present in all tumors, except for pure immature teratomas. CONCLUSION: We here present the first whole exome sequencing data and to our knowledge the largest CNA study in OGCT. We confirmed that earlier reported KIT mutations were frequent in dysgerminomas and mixed forms with a dysgerminoma component, whereas chromosome 12p gains were present in all histological subtypes except pure immature teratomas. We detected recurrent KRAS mutations, recurrent focal deletions and an enrichment in the PI3K/AKT/PTEN pathway in yolk sac tumors. Several of these aberrations involve targetable pathways, offering novel treatment modalities for OGCT.

Asparaginase-like protein 1 is an independent prognostic marker in primary endometrial cancer, and is frequently lost in metastatic lesions.

OBJECTIVE: Loss of Asparaginase-like protein 1 (ASRGL1) has been suggested as a prognostic biomarker in endometrial carcinoma. Our objective was to validate this in a prospectively collected, independent patient cohort, and evaluate ASRGL1 expression in endometrial carcinoma precursor lesion and metastases. METHODS: 782 primary endometrial carcinomas, 90 precursor lesions (complex atypical hyperplasia), and 179 metastases (from 87 patients) were evaluated for ASRGL1 expression by immunohistochemistry in relation to clinical and histopathological data. ASRGL1 mRNA level was investigated in 237 primary tumors and related to survival and ASRGL1 protein expression. RESULTS: Low expression of ASRGL1 protein and ASRGL1 mRNA predicted poor disease specific survival (P<0.001). In multivariate survival analyses ASRGL1 had independent prognostic value both in the whole patient cohort (Hazard ratio (HR): 1.53, 95% confidence interval (CI): 1.04-2.26, P=0.031) and within the endometrioid subgroup (HR: 2.64, CI: 1.47-4.74, P=0.001). Low ASRGL1 expression was less frequent in patients with low grade endometrioid primary tumors compared to high grade endometrioid and non-endometrioid primary tumors, and ASRGL1 was lost in the majority of metastatic lesions. CONCLUSIONS: In a prospective setting ASRGL1 validates as a strong prognostic biomarker in endometrial carcinoma. Loss of ASRGL1 is associated with aggressive disease and poor survival, and is demonstrated for the first time to have independent prognostic value in the entire endometrial carcinoma patient population.

Added Value of Estrogen Receptor, Progesterone Receptor, and L1 Cell Adhesion Molecule Expression to Histology-Based Endometrial Carcinoma Recurrence Prediction Models: An ENITEC Collaboration Study.

OBJECTIVES: Endometrial carcinoma mortality is mainly caused by recurrent disease, and various immunohistochemical markers to predict recurrences have been studied. Loss of the estrogen receptor (ER) and progesterone receptor (PR) and the presence of the L1 cell adhesion molecule (L1CAM) are promising markers, but their combined value has not been studied. MATERIALS AND METHODS: Expression of ER, PR, and L1CAM was immunohistochemically determined in 293 endometrial carcinomas from 11 collaborating European Network for Individualized Treatment of Endometrial Cancer centers. Estrogen receptor, PR, or L1CAM staining was considered positive or negative when expressed by greater than or equal to 10% or less than 10% of the tumor cells, respectively. The association between these markers and clinicopathological markers, and their combined value in predicting survival were calculated, both in the entire cohort and in a selected groups of stage I endometrioid and low-risk stage I endometrioid carcinomas. RESULTS: Estrogen receptor and PR were negative in 19% and 28% of the cases, respectively, and L1CAM was positive in 18%. All 3 were associated with advanced stage, high-grade, nonendometrioid histology, lymphovascular space invasion (LVSI), and reduced disease-free survival. Only advanced stage, loss of PR, and LVSI were associated with reduced disease-free survival in multivariate analysis. A prognostic model including these 3 markers was superior to 1 including only the 3 immunohistochemical markers, which was superior to the traditional model. In both the stage I endometrioid and the low-risk stage I endometrioid groups, only loss of PR was associated with reduced disease-free survival. CONCLUSIONS: Loss of ER and PR, and the presence of L1CAM are associated with high risk characteristics, and loss of PR is the strongest predictor of recurrent disease. Although a combination of these 3 markers is slightly superior to the traditional histological markers, a prognostic model including stage, PR expression, and LVSI is the most promising model in the identification of high risk carcinomas. In the stage I endometrioid carcinomas, PR immunohistochemistry appears to be of additional value in predicting recurrences.

Somatic mutation profiles of clear cell endometrial tumors revealed by whole exome and targeted gene sequencing.

BACKGROUND: The molecular pathogenesis of clear cell endometrial cancer (CCEC), a tumor type with a relatively unfavorable prognosis, is not well defined. We searched exome-wide for novel somatically mutated genes in CCEC and assessed the mutational spectrum of known and candidate driver genes in a large cohort of cases. METHODS: We conducted whole exome sequencing of paired tumor-normal DNAs from 16 cases of CCEC (12 CCECs and the CCEC components of 4 mixed histology tumors). Twenty-two genes-of-interest were Sanger-sequenced from another 47 cases of CCEC. Microsatellite instability (MSI) and microsatellite stability (MSS) were determined by genotyping 5 mononucleotide repeats. RESULTS: Two tumor exomes had relatively high mutational loads and MSI. The other 14 tumor exomes were MSS and had 236 validated nonsynonymous or splice junction somatic mutations among 222 protein-encoding genes. Among the 63 cases of CCEC in this study, we identified frequent somatic mutations in TP53 (39.7%), PIK3CA (23.8%), PIK3R1 (15.9%), ARID1A (15.9%), PPP2R1A (15.9%), SPOP (14.3%), and TAF1 (9.5%), as well as MSI (11.3%). Five of 8 mutations in TAF1, a gene with no known role in CCEC, localized to the putative histone acetyltransferase domain and included 2 recurrently mutated residues. Based on patterns of MSI and mutations in 7 genes, CCEC subsets molecularly resembled serous endometrial cancer (SEC) or endometrioid endometrial cancer (EEC). CONCLUSION: Our findings demonstrate molecular similarities between CCEC and SEC and EEC and implicate TAF1 as a novel candidate CCEC driver gene. Cancer 2017;123:3261-8. © 2017 American Cancer Society.

Expression of L1CAM in curettage or high L1CAM level in preoperative blood samples predicts lymph node metastases and poor outcome in endometrial cancer patients.

BACKGROUND: Several studies have identified L1 cell adhesion molecule (L1CAM) as a strong prognostic marker in endometrial cancer. To further underline the clinical usefulness of this biomarker, we investigated L1CAM as a predictive marker for lymph node metastases and its prognostic impact in curettage specimens and preoperative plasma samples. In addition, we aimed to validate the prognostic value of L1CAM in hysterectomy specimen. METHODS: Immunohistochemical staining of L1CAM was performed for 795 hysterectomy and 1134 curettage specimen from endometrial cancer patients. The L1CAM level in preoperative blood samples from 372 patients was determined using ELISA. RESULTS: Expression of L1CAM in curettage specimen was significantly correlated to L1CAM level in corresponding hysterectomy specimen (P<0.001). Both in curettage and preoperative plasma samples L1CAM upregulation was significantly associated with features of aggressive disease and poor outcome (P<0.001). The L1CAM was an independent predictor of lymph node metastases, after correction for curettage histology, both in curettage specimen (P=0.002) and plasma samples (P=0.048). In the hysterectomy samples L1CAM was significantly associated with poor outcome (P<0.001). CONCLUSIONS: We demonstrate that preoperative evaluation of L1CAM levels, both in curettage or plasma samples, predicts lymph node metastases and adds valuable information on patient prognosis.

Cerebellar degeneration-related proteins 2 and 2-like are present in ovarian cancer in patients with and without Yo antibodies.

BACKGROUND: Cerebellar degeneration-related protein 2 (CDR2) has been presumed to be the main antigen for the onconeural antibody Yo, which is strongly associated with ovarian cancer and paraneoplastic cerebellar degeneration (PCD). Recent data show that Yo antibodies also target the CDR2-like protein (CDR2L). We, therefore, examined the expression of CDR2 and CDR2L in ovarian cancer tissue from patients with and without Yo antibodies and from various other cancerous and normal human tissues. METHODS: Ovarian cancer tissue and serum samples from 16 patients were included in the study (four with anti-Yo and PCD, two with anti-Yo without PCD, five with only CDR2L antibodies, and five without onconeural antibodies). Clinical data were available for all patients. The human tissues were examined by western blot and immunohistochemistry using rabbit CDR2 and CDR2L antibodies. RESULTS: Ovarian cancers from all 16 patients expressed CDR2 and CDR2L proteins. Both proteins were also present in normal and cancer tissue from mammary tissue, kidney, ovary, prostate, and testis. CONCLUSION: CDR2L is present in ovarian cancers from patients with and without Yo antibodies as was shown previously for CDR2. In addition, both CDR2 and CDR2L proteins are more widely expressed than previously thought, both in normal and cancerous tissues.