Association of glutaminase expression with immune-suppressive tumor microenvironment, clinicopathologic features, and clinical outcomes in endometrial cancer.

OBJECTIVE: Increased glutamine metabolism by cancer cells via upregulation of the drug-targetable enzyme glutaminase may contribute to an immune-suppressive tumor microenvironment. Inhibiting glutamine metabolism can not only suppress tumor growth, but also enhance tumor-specific immunity. We investigated the relationship between glutaminase expression, the immune tumor microenvironment, and clinicopathologic features in endometrial cancer. METHODS: Tissue microarrays constructed from 87 primary endometrial cancer specimens were stained by immunohistochemistry for glutaminase, c-Myc, mutL homolog 1 (MLH1), mutS homolog 2 (MSH2), mutS homolog 6 (MSH6), postmeiotic segregation increased 2 (PMS2), estrogen receptor (ER), progresterone receptor (PR), CD8, FoxP3, CD68, programmed cell death protein 1 (PD-1), and programmed cell death ligand 1 (PD-L1). We compared the immune tumor microenvironment and clinicopathologic features between glutaminase-high (H-score≥median) versus glutaminase-low (H-score

ARID1A Regulates Progesterone Receptor Expression in Early Endometrial Endometrioid Carcinoma Pathogenesis.

Loss of progesterone receptor (PR) expression is an established risk factor for unresponsiveness to progesterone therapy in patients with endometrial atypical hyperplasia and endometrioid carcinoma. ARID1A is one of the most commonly mutated genes in endometrioid carcinomas, and the loss of its expression is associated with tumor progression. In this study, we investigated the roles of ARID1A deficiency in PR expression in human and murine endometrial epithelial neoplasia. An analysis of genome-wide chromatin immunoprecipitation sequencing in isogenic ARID1A-/- and ARID1A+/+ human endometrial epithelial cells revealed that ARID1A-/- cells showed significantly reduced chromatin immunoprecipitation sequencing signals for ARID1A, BRG1, and H3K27AC in the PgR enhancer region. We then performed immunohistochemistry to correlate the protein expression levels of ARID1A, estrogen receptor, and PR in 50 human samples of endometrial atypical hyperplasia and 75 human samples of endometrial carcinomas. The expression levels of PR but not were significantly lower in ARID1A-deficient low-grade endometrial carcinomas and atypical hyperplasia (P = .0002). When Pten and Pten/Arid1a conditional knockout murine models were used, Pten-/-;Arid1a-/- mice exhibited significantly decreased epithelial PR expression in endometrial carcinomas (P = .003) and atypical hyperplasia (P < .0001) compared with that in the same tissues from Pten-/-;Arid1a+/+ mice. Our data suggest that the loss of ARID1A expression, as occurs in ARID1A-mutated endometrioid carcinomas, decreases PgR transcription by modulating the PgR enhancer region during early tumor development.

Case Report: Tubal Atypical Placental Site Nodule.

Placental site nodule (PSN) is a benign proliferation of chorionic-type intermediate trophoblastic cells that forms a tumor-like lesion. Most PSNs are intrauterine, but a few have been reported outside the uterus, including in fallopian tubes. PSN is related to epithelioid trophoblastic tumor (ETT) in that both are composed of chorionic-type intermediate trophoblastic cells, while ETT is hypercellular and contains trophoblastic cells with increased nuclear atypia and a higher Ki-67 proliferation index as compared with PSN. Occasionally, an intermediate stage between a PSN and an ETT is observed, and such a lesion is often recognized as an atypical PSN (aPSN) characterized by trophoblastic cells exhibiting morphologic features in transition from a conventional PSN to an ETT. aPSN has been thought to exhibit benign behavior; however, it has also been reported that up to 15% of aPSN lesions either coexist with, or subsequently develop into, ETT. To the best of our knowledge, there has been no case report of an aPSN in an extrauterine site. Here, we reported a highly unusual case of tubal aPSN, which illustrates several key features associated with PSN and its possible pathogenesis.

Genome-wide mutation analysis in precancerous lesions of endometrial carcinoma.

Clinicopathological evidence supports endometrial atypical hyperplasia (AH) or endometrial intraepithelial neoplasia as the precursor of uterine endometrioid carcinoma (EC), the most common gynecologic malignancy. However, the pathogenic progression from AH to EC remains unclear. Here, we employed whole-exome sequencing to identify somatic mutations and copy number changes in micro-dissected lesions from 30 pairs of newly diagnosed AH and EC. We found that all but one pair of AHs shared the same DNA mismatch repair status as their corresponding ECs. The percentage of common mutations between AH lesions and corresponding ECs varied significantly, ranging from 0.1% to 82%. Microsatellite stable AHs had fewer cancer driver mutations than ECs (5 versus 7, p = 0.017), but among microsatellite unstable AHs and ECs there was no difference in mutational numbers (36 versus 38, p = 0.65). As compared to AH specimens, 19 (79%) of 24 microsatellite stable EC tumors gained new cancer driver mutations, most of which involved PTEN, ARID1A, PIK3CA, CTNNB1, or CHD4. Our results suggest that some AH lesions are the immediate precursor of ECs, and progression depends on acquisition of additional cancer driver mutations. However, a complex clonal relationship between AH and EC can also be appreciated, as in some cases both lesions diverge very early or arise independently, thus co-developing with distinct genetic trajectories. Our genome-wide profile of mutations in AH and EC shines new light on the molecular landscape of tumor progression. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Long Interspersed Nuclear Element 1 Retrotransposons Become Deregulated during the Development of Ovarian Cancer Precursor Lesions.

There is growing evidence that most high-grade serous ovarian carcinomas likely arise from local dissemination of precursor lesions of the fallopian tube. Evolution of these lesions from early p53 signatures to latter-stage, serous tubal intraepithelial carcinomas (STICs) is characterized by cytologic atypia, accumulation of somatic mutations, and genomic instability, the etiologies of which remain unclear. Long interspersed element 1 (LINE-1) retrotransposon is expressed in many carcinomas, including high-grade serous ovarian carcinoma, where it contributes to genomic instability; however, the timing of LINE-1 activation during this evolution has yet to be elucidated. In this study, we assessed LINE-1 open reading frame 1 protein expression in 12 p53 signature lesions, 32 STICs, and 112 various types of ovarian cancers via immunohistochemical staining and examined LINE-1 promoter methylation in representative cases. We found that 78% and 57% of STICs, with and without concurrent ovarian carcinomas, respectively, exhibited intense LINE-1 immunoreactivity compared with adjacent, normal-appearing fallopian tube epithelium. Hypomethylation of the LINE-1 promoter was found in all STICs exhibiting overexpression. None of the 12 p53 signatures demonstrated significant LINE-1 expression. In ovarian cancer, 84 (75%) of 112 ovarian carcinomas overexpressed LINE-1. Our results indicate that LINE-1 retrotransposons often become deregulated during progression of ovarian cancer precursor lesions from the p53 signature to STIC stages and remain highly expressed in carcinoma.

Adjuvant therapy for early stage, endometrial cancer with lymphovascular space invasion: Is there a role for chemotherapy?

OBJECTIVES: Lymphovascular space invasion (LVSI) is an independent risk factor for recurrence and poor survival in early-stage endometrioid endometrial cancer (EEC), but optimal adjuvant treatment is unknown. We aimed to compare the survival of women with early-stage EEC with LVSI treated postoperatively with observation (OBS), radiation (RAD, external beam and/or vaginal brachytherapy), or chemotherapy (CHEMO)+/-RAD. METHODS: This was a multi-institutional, retrospective cohort study of women with stage I or II EEC with LVSI who underwent hysterectomy+/-lymphadenectomy from 2005 to 2015 and received OBS, RAD, or CHEMO+/-RAD postoperatively. Progression-free survival and overall survival were evaluated using Kaplan-Meier estimates and Cox proportional hazards models. RESULTS: In total, 478 women were included; median age was 64 years, median follow-up was 50.3 months. After surgery, 143 (30%) underwent OBS, 232 (48.5%) received RAD, and 103(21.5%) received CHEMO+/-RAD (95% of whom received RAD). Demographics were similar among groups, but those undergoing OBS had lower stage and grade. A total of 101 (21%) women recurred. Progression-free survival (PFS) was improved in both CHEMO+/-RAD (HR = 0.18, 95% CI: 0.09-0.39) and RAD (HR = 0.31, 95% CI: 0.18-0.54) groups compared to OBS, though neither adjuvant therapy was superior to the other. However, in grade 3 tumors, the CHEMO+/-RAD group had superior PFS compared to both RAD (HR 0.25; 95% CI: 0.12-0.52) and OBS cohorts (HR = 0.10, 95% CI: 0.03-0.32). Overall survival did not differ by treatment. CONCLUSIONS: In early-stage EEC with LVSI, adjuvant therapy improved PFS compared to observation alone. In those with grade 3 EEC, adjuvant chemotherapy with or without radiation improved PFS compared to observation or radiation alone.

Molecular Classification and Emerging Targeted Therapy in Endometrial Cancer.

Recent advances in molecular studies, especially genome-wide analyses, have revealed the landscape of genomic alterations present in endometrial carcinomas, and have provided valuable insight into the pathogenesis of this disease. The current challenges are in developing a molecular-morphologic classification system to enhance traditional pathologic diagnosis and in determining the optimal approach to using this new information to guide clinical management. Molecular assays may be particularly beneficial in allowing the earlier detection of endometrial cancer or precursor lesions and in guiding personalized treatment approaches. In this review, we describe the current molecular landscape of endometrial cancers, efforts underway to incorporate molecular alterations into the current classification systems, and the development of diagnostic tools for the early detection of endometrial cancer. Finally, we present opportunities for using these data to tailor therapeutic strategies. A comprehensive understanding of the molecular alterations responsible for the origination, relapse, and resistance patterns of this disease will ultimately improve outcomes for patients with endometrial cancer.

Adjuvant treatment improves overall survival in women with high-intermediate risk early-stage endometrial cancer with lymphovascular space invasion.

BACKGROUND: Adjuvant therapy in early-stage endometrial cancer has not shown a clear overall survival benefit, and hence, patient selection remains crucial. OBJECTIVE: To determine whether women with high-intermediate risk, early-stage endometrial cancer with lymphovascular space invasion particularly benefit from adjuvant treatment in improving oncologic outcomes. METHODS: A multi-center retrospective study was conducted in women with stage IA, IB, and II endometrial cancer with lymphovascular space invasion who met criteria for high-intermediate risk by Gynecologic Oncology Group (GOG) 99. Patients were stratified by the type of adjuvant treatment received. Clinical and pathologic features were abstracted. Progression-free and overall survival were evaluated using multivariable analysis. RESULTS: 405 patients were included with the median age of 67 years (range 27-92, IQR 59-73). 75.0% of the patients had full staging with lymphadenectomy, and 8.6% had sentinel lymph node biopsy (total 83.6%). After surgery, 24.9% of the patients underwent observation and 75.1% received adjuvant therapy, which included external beam radiation therapy (15.1%), vaginal brachytherapy (45.4%), and combined brachytherapy + chemotherapy (19.1%). Overall, adjuvant treatment resulted in improved oncologic outcomes for both 5-year progression-free survival (77.2% vs 69.6%, HR 0.55, p=0.01) and overall survival (81.5% vs 60.2%, HR 0.42, p<0.001). After adjusting for stage, grade 2/3, and age, improved progression-free survival and overall survival were observed for the following adjuvant subgroups compared with observation: external beam radiation (overall survival HR 0.47, p=0.047, progression-free survival not significant), vaginal brachytherapy (overall survival HR 0.35, p<0.001; progression-free survival HR 0.42, p=0.003), and brachytherapy + chemotherapy (overall survival HR 0.30 p=0.002; progression-free survival HR 0.35, p=0.006). Compared with vaginal brachytherapy alone, external beam radiation or the addition of chemotherapy did not further improve progression-free survival (p=0.80, p=0.65, respectively) or overall survival (p=0.47, p=0.74, respectively). CONCLUSION: Adjuvant therapy improves both progression-free survival and overall survival in women with early-stage endometrial cancer meeting high-intermediate risk criteria with lymphovascular space invasion. External beam radiation or adding chemotherapy did not confer additional survival advantage compared with vaginal brachytherapy alone.

T cell-inflamed phenotype and increased Foxp3 expression in infiltrating T-cells of mismatch-repair deficient endometrial cancers.

Mismatch repair-deficient endometrial cancers have a high somatic mutation burden, suggesting that patients with these tumors may benefit from immunotherapy. Elucidating the immune suppressive mechanisms of mismatch repair-deficient endometrial cancers is fundamental to developing future immune-based interventions. This study aimed to determine the immune cell populations associated with mismatch repair-deficient endometrial cancers, especially focusing on targetable regulatory pathways of the immune response. A total of 76 endometrial cancer hysterectomy specimens were evaluated for tumor-infiltrating immune cells by immunohistochemistry. Immune specific markers were used to evaluate each specimen for the number of CD8 + cytotoxic T lymphocytes, forkhead-box P3 (FoxP3) + regulatory T cells, CD68 + tumor-associated macrophages, as well as programmed death-1 (PD-1) + immune cells, and the percentage of programmed death ligand-1 (PD-L1) + immune cells. Mismatch repair-deficient tumors exhibited a significantly higher number of CD8 + cytotoxic T lymphocytes (p = 0.0006), FoxP3 + regulatory T cells (p = 0.0003), PD-1 + immune cells (p = 0.0069), and a higher percentage of PD-L1 + immune cells (p = 0.0007) occupying the tumor compared to mismatch repair-proficient endometrial cancers. There was no significant difference in CD68 + tumor-associated macrophages infiltration between the two groups. Endometrial cancers with tumor PD-L1 expression also showed significantly increased infiltration of CD8 + cytotoxic T lymphocytes (p = 0.0002), FoxP3 + regulatory T cells (p = 0.0003), PD-1 + immune cells (p < 0.0001), and PD-L1 + immune cells (p < 0.0001). Endometrial cancers showing mismatch repair-deficiency and PD-L1 expression in tumor cells exhibit a prominent T cell-inflamed phenotype. More importantly, the increased number of FoxP3 + regulatory T cells in mismatch repair-deficient endometrial cancers suggests that combination therapy by targeting both regulatory T cells and immune checkpoints may be warranted to improve clinical efficacy.

Recurrence, death, and secondary malignancy after ovarian conservation for young women with early-stage low-grade endometrial cancer.

OBJECTIVE: To examine the association between ovarian conservation and oncologic outcome in surgically-treated young women with early-stage, low-grade endometrial cancer. METHODS: This multicenter retrospective study examined women aged <50 with stage I grade 1-2 endometrioid endometrial cancer who underwent primary surgery with hysterectomy from 2000 to 2014 (US cohort n = 1196, and Japan cohort n = 495). Recurrence patterns, survival, and the presence of a metachronous secondary malignancy were assessed based on ovarian conservation versus oophorectomy. RESULTS: During the study period, the ovarian conservation rate significantly increased in the US cohort from 5.4% to 16.4% (P = 0.020) whereas the rate was unchanged in the Japan cohort (6.3-8.7%, P = 0.787). In the US cohort, ovarian conservation was not associated with disease-free survival (hazard ratio [HR] 0.829, 95% confidence interval [CI] 0.188-3.663, P = 0.805), overall survival (HR not estimated, P = 0.981), or metachronous secondary malignancy (HR 1.787, 95% CI 0.603-5.295, P = 0.295). In the Japan cohort, ovarian conservation was associated with decreased disease-free survival (HR 5.214, 95% CI 1.557-17.464, P = 0.007) and an increased risk of a metachronous secondary malignancy, particularly ovarian cancer (HR 7.119, 95% CI 1.349-37.554, P = 0.021), but was not associated with overall survival (HR not estimated, P = 0.987). Ovarian recurrence or metachronous secondary ovarian cancer occurred after a median time of 5.9 years, and all cases were salvaged. CONCLUSION: Our study suggests that adoption of ovarian conservation in young women with early-stage low-grade endometrial cancer varies by population. Ovarian conservation for young women with early-stage, low-grade endometrial cancer may be potentially associated with increased risks of ovarian recurrence or metachronous secondary ovarian cancer in certain populations; nevertheless, ovarian conservation did not negatively impact overall survival.

Loss of ARID1A expression in endometrial samplings is associated with the risk of endometrial carcinoma.

OBJECTIVES: Inactivating somatic mutations of ARID1A, a chromatin remodeling gene, are common in endometrioid endometrial carcinoma (EEC) but rare in complex atypical hyperplasia (CAH). Our objectives were to determine the clinical significance of ARID1A loss during tumor progression from CAH to EEC and to assess its role as a predictive cancer biomarker. METHODS: In cohort A, ARID1A immunoreactivity was evaluated in endometrial sampling (biopsy/curettage) specimens showing CAH to determine whether ARID1A expression correlates with the presence of EEC at subsequent hysterectomy. In cohort B, ARID1A immunoreactivity was evaluated in the hysterectomy specimens with concurrent CAH and EEC to assess for the concordance of ARID1A expression in both components. RESULTS: In cohort A, loss of ARID1A immunoreactivity was identified in the endometrial sampling specimen of 31% of patients undergoing hysterectomy for a preoperative diagnosis of CAH. EEC was identified in the hysterectomy specimen of 94% of patients with loss of ARID1A in the endometrial sampling specimen while only 15% of patients with retained ARID1A expression (P < 0.0001). No association was observed between ARID1A expression and demographic characteristics. In cohort B, 14 (31%) of 45 patients with concurrent CAH/EEC in their hysterectomy specimens had complete loss of ARID1A expression in the EEC components. Among these 14 patients, 50% also had loss of ARID1A immunoreactivity in the CAH component. CONCLUSIONS: ARID1A immunostaining may correlate with malignant transformation and the presence of concurrent EEC in patients with CAH identified at pre-hysterectomy endometrial sampling. Further investigation to determine the potential utility of ARID1A expression as a tissue biomarker is warranted.

Narcotics reduction, quality and safety in gynecologic oncology surgery in the first year of enhanced recovery after surgery protocol implementation.

OBJECTIVES: Enhanced Recovery After Surgery (ERAS) programs are mechanisms for achieving value-based improvements in surgery. This report provides a detailed analysis of the impact of an ERAS program on patient outcomes as well as quality and safety measures during implementation on a gynecologic oncology service at a major academic medical center. METHODS: A retrospective review of gynecologic oncology patients undergoing elective laparotomy during the implementation phase of an ERAS program (January 2016 through December 2016) was performed. Patient demographics, surgical variables, postoperative outcomes, and adherence to core safety measures, including antimicrobial and venous thromboembolism (VTE) prophylaxis, were compared to a historical patient cohort (January 2015 through December 2015). Statistical analyses were performed using t-tests, Wilcoxon rank sum tests, and Chi squared tests. RESULTS: The inaugural 109 ERAS program participants were compared to a historical patient cohort (n=158). There was no difference in BMI, race, malignancy, or complexity of procedure between cohorts. ERAS patients required less narcotics (70.7 vs 127.4, p=0.007, oral morphine equivalents) and PCA use (32.1% vs. 50.6%, p=0.002). Despite this substantial reduction in narcotics, ERAS patients did not report more pain and in fact reported significantly less pain by postoperative day 3. There were no differences in length of stay (5days), complication rates (13.8% vs. 20.3%, p=0.17) or 30-day readmission rates (9.5 vs 11.9%, p=0.54) between ERAS and historical patients, respectively. Compliance with antimicrobial prophylaxis was 97.2%. However, 33.9% of ERAS patients received substandard preoperative VTE prophylaxis. CONCLUSIONS: ERAS program implementation resulted in reductions in narcotic requirements and PCA use without changes in length of stay or readmission rates. Compliance should be diligently audited during the implementation phase of ERAS programs, with special attention to adherence to pre-existing core safety measures.

Minimally invasive hysterectomy surgery rates for endometrial cancer performed at National Comprehensive Cancer Network (NCCN) Centers.

OBJECTIVES: Minimally invasive surgery (MIS) is a quality measure for endometrial cancer (EC) established by the Society of Gynecologic Oncology and the American College of Surgeons. Our study objective was to assess the proportion of EC cases performed by MIS at National Comprehensive Cancer Network (NCCN) centers and evaluate perioperative outcomes. METHODS: A retrospective cohort study of women who underwent surgical treatment for EC from 2013 to 2014 was conducted at four NCCN centers. Multivariable mixed logistic regression models analyzed factors associated with failure to perform MIS and perioperative complications. RESULTS: In total 1621 patients were evaluated; 86.5% underwent MIS (robotic-assisted 72.5%, laparoscopic 20.9%, vaginal 6.6%). On multivariable analysis, factors associated with failure to undergo MIS were uterine size >12cm (Odds Ratio [OR]: 0.17, 95% CI 0.03-0.9), stage III (OR: 0.16, 95% CI 0.05-0.49) and IV disease (OR: 0.07, 95% CI 0.02-0.22). For stage I/II disease, complications occurred in 5.1% of MIS and 21.7% of laparotomy cases (p<0.01). Laparotomy was associated with increases in any complication (OR: 6.0, 95% CI 3.3-10.8), gastrointestinal (OR: 7.2, 95% CI 2.6-19.5), wound (OR: 3.7, 95% CI 1.5-9.2), respiratory (OR 37.5, 95% CI 3.9-358.0), VTE (OR 10.5, 95% CI 1.3-82.8) and 30-day readmission (OR: 2.6, 95% CI 1.4-4.9) compared to MIS. CONCLUSIONS: At NCCN-designated centers, the MIS hysterectomy rate in EC is higher than the published national average, with low perioperative complications. Previously identified disparities of age, race, and BMI were not observed. A proposed MIS hysterectomy benchmark of >80% in EC care is feasible when performed at high volume centers.

Utilization and cost of cell salvage in minimally invasive myomectomy.

OBJECTIVE: To assess the utilization and cost of intraoperative cell salvage (ICS) in minimally invasive myomectomy. STUDY DESIGN: Retrospective cohort study of patients who underwent minimally invasive myomectomy at a quaternary care academic hospital. Patients were classified into: ICS setup vs no ICS setup, ICS setup with reinfusion vs ICS setup without reinfusion. RESULTS: Of 382 patients who underwent minimally invasive myomectomy, 67 (17.5 %) had ICS setup, 30 (44.8 %) of those patients reinfused. Median volume of reinfusion per patient was 300 mL (range 125-1000 mL). Patients who ultimately underwent ICS reinfusion, compared to those with ICS setup only, had significantly larger mean maximum fibroid size (9.8 cm vs 8.0 cm, p = 0.02), higher median total specimen weight (367 vs 304 g, p = 0.03), higher median estimated blood loss (575 vs 300 mL, p < 0.0001), longer mean operative time (261 vs 215 min, p = 0.04). No perioperative complications were associated with ICS. Higher costs are associated with universal use or complete lack of ICS; lowest cost is associated with ICS setup only for those ultimately reinfused. CONCLUSION: ICS might reduce requirements for allogeneic blood transfusions in patients undergoing minimally invasive myomectomy, and may contribute to cost savings. Uterine and maximum fibroid sizes are possible preoperative indicators for patients who require cell salvage reinfusion.

Laparoscopic surgical access in morbidly obese women undergoing endometrial cancer surgery: Repurposing the left upper quadrant approach.

OBJECTIVE: The study purpose was to report the outcomes of patients undergoing endometrial cancer surgical staging with laparoscopic abdominal access entry using a left upper quadrant (LUQ) access technique. METHODS: This was a retrospective cohort study conducted from 1 January 2013 to 1 January 2018. The setting was an academic, single institution gynecologic oncology service with a high volume of minimally invasive surgery (MIS). The patient cohort included obese (defined as BMI > 30 kg/m2) or morbidly obese (BMI > 40 kg/m2) women undergoing MIS for endometrial cancer staging. All patients underwent laparoscopic abdominal access via a 5-mm or 10-mm optical trocar system using a LUQ technique. RESULTS: In total, 317 patients were included with a median age of 54 years (range, 24-79) and median BMI 42.5 kg/m2 (range, 32-70); 60 % morbidly obese. Successful LUQ access was achieved in 98.1 %. Of those with a failed LUQ approach, two had undergone previous LUQ surgery and 4 had ≥1 previous midline vertical incisions. There was one LUQ trocar-related visceral injury (0.3 %) and no vascular injuries during the study period. CONCLUSION: A LUQ abdominal technique is a safe and reliable method of laparoscopic access in morbidly obese women undergoing MIS for endometrial cancer staging. This may be the preferred method of laparoscopic access for women with a panniculus or central adiposity, given the caudal displacement of the umbilicus and poor correlation with intraperitoneal anatomic landmarks in this setting.

Inhibition of the MYC-Regulated Glutaminase Metabolic Axis Is an Effective Synthetic Lethal Approach for Treating Chemoresistant Ovarian Cancers.

Amplification and overexpression of the MYC oncogene in tumor cells, including ovarian cancer cells, correlates with poor responses to chemotherapy. As MYC is not directly targetable, we have analyzed molecular pathways downstream of MYC to identify potential therapeutic targets. Here we report that ovarian cancer cells overexpressing glutaminase (GLS), a target of MYC and a key enzyme in glutaminolysis, are intrinsically resistant to platinum-based chemotherapy and are enriched with intracellular antioxidant glutathione. Deprivation of glutamine by glutamine-withdrawal, GLS knockdown, or exposure to the GLS inhibitor CB-839 resulted in robust induction of reactive oxygen species in high GLS-expressing but not in low GLS-expressing ovarian cancer cells. Treatment with CB-839 rendered GLShigh cells vulnerable to the poly(ADP-ribose) polymerase (PARP) inhibitor, olaparib, and prolonged survival in tumor-bearing mice. These findings suggest consideration of applying a combined therapy of GLS inhibitor and PARP inhibitor to treat chemoresistant ovarian cancers, especially those with high GLS expression. SIGNIFICANCE: Targeting glutaminase disturbs redox homeostasis and nucleotide synthesis and causes replication stress in cancer cells, representing an exploitable vulnerability for the development of effective therapeutics. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/20/4514/F1.large.jpg.

Methylomic Analysis of Ovarian Cancers Identifies Tumor-Specific Alterations Readily Detectable in Early Precursor Lesions.

PURPOSE: High-grade serous ovarian carcinoma (HGSOC) typically remains undiagnosed until advanced stages when peritoneal dissemination has already occurred. Here, we sought to identify HGSOC-specific alterations in DNA methylation and assess their potential to provide sensitive and specific detection of HGSOC at its earliest stages. EXPERIMENTAL DESIGN: MethylationEPIC genome-wide methylation analysis was performed on a discovery cohort comprising 23 HGSOC, 37 non-HGSOC malignant, and 36 histologically unremarkable gynecologic tissue samples. The resulting data were processed using selective bioinformatic criteria to identify regions of high-confidence HGSOC-specific differential methylation. Quantitative methylation-specific real-time PCR (qMSP) assays were then developed for 8 of the top-performing regions and analytically validated in a cohort of 90 tissue samples. Lastly, qMSP assays were used to assess and compare methylation in 30 laser-capture microdissected (LCM) fallopian tube epithelia samples obtained from cancer-free and serous tubal intraepithelial carcinoma (STIC) positive women. RESULTS: Bioinformatic selection identified 91 regions of robust, HGSOC-specific hypermethylation, 23 of which exhibited an area under the receiver-operator curve (AUC) value ≥ 0.9 in the discovery cohort. Seven of 8 top-performing regions demonstrated AUC values between 0.838 and 0.968 when analytically validated by qMSP in a 90-patient cohort. A panel of the 3 top-performing genes (c17orf64, IRX2, and TUBB6) was able to perfectly discriminate HGSOC (AUC 1.0). Hypermethylation within these loci was found exclusively in LCM fallopian tube epithelia from women with STIC lesions, but not in cancer-free fallopian tubes. CONCLUSIONS: A panel of methylation biomarkers can be used to accurately identify HGSOC, even at precursor stages of the disease.

Evaluation of liquid from the Papanicolaou test and other liquid biopsies for the detection of endometrial and ovarian cancers.

We report the detection of endometrial and ovarian cancers based on genetic analyses of DNA recovered from the fluids obtained during a routine Papanicolaou (Pap) test. The new test, called PapSEEK, incorporates assays for mutations in 18 genes as well as an assay for aneuploidy. In Pap brush samples from 382 endometrial cancer patients, 81% [95% confidence interval (CI), 77 to 85%] were positive, including 78% of patients with early-stage disease. The sensitivity in 245 ovarian cancer patients was 33% (95% CI, 27 to 39%), including 34% of patients with early-stage disease. In contrast, only 1.4% of 714 women without cancer had positive Pap brush samples (specificity, ~99%). Next, we showed that intrauterine sampling with a Tao brush increased the detection of malignancy over endocervical sampling with a Pap brush: 93% of 123 (95% CI, 87 to 97%) patients with endometrial cancer and 45% of 51 (95% CI, 31 to 60%) patients with ovarian cancer were positive, whereas none of the samples from 125 women without cancer were positive (specificity, 100%). Finally, in 83 ovarian cancer patients in whom plasma was available, circulating tumor DNA was found in 43% of patients (95% CI, 33 to 55%). When plasma and Pap brush samples were both tested, the sensitivity for ovarian cancer increased to 63% (95% CI, 51 to 73%). These results demonstrate the potential of mutation-based diagnostics to detect gynecologic cancers at a stage when they are more likely to be curable.