Randall K. Gibb

Prevalence of defective DNA mismatch repair and MSH6 mutation in an unselected series of endometrial cancers

Endometrial cancer is the most common gynecologic malignancy in the United States and the most frequent extracolonic tumor in hereditary nonpolyposis colorectal cancer (HNPCC). HNPCC patients have inherited defects in DNA mismatch repair and the microsatellite instability (MSI) tumor phenotype. Sporadic endometrial cancers also exhibit MSI, usually associated with methylation of the MLH1 promoter. Germ-line MSH6 mutations, which are rare in HNPCC, have been reported in several families with multiple members affected with endometrial carcinoma. We reasoned that MSH6 mutation might account for loss of mismatch repair in MSI-positive endometrial cancers in which the cause of MSI is unknown. We therefore investigated MSI and MLH1 promoter methylation in 441 endometrial cancer patients unselected for age or personal and family history of cancers. MSI and MLH1 promoter methylation status were associated with age of onset and tumor histology. One hundred cases (23% of the entire series) were evaluated for MSH6 defects. Inactivating germ-line MSH6 mutations were identified in seven women with MSI-positive, MLH1 promoter unmethylated cancers. Most of the MSI in these cases was seen with mononucleotide repeat markers. The MSH6 mutation carriers were significantly younger than the rest of the population (mean age 54.8 versus 64.6, P = 0.04). Somatic mutations were seen in 17 tumors, all of which had MSI. Our data suggest that inherited defects in MSH6 in women with endometrial cancer are relatively common. The minimum estimate of the prevalence of inherited MSH6 mutation in endometrial cancer is 1.6% (7 of 441), comparable with the predicted prevalence for patients with colorectal cancer.

Bevacizumab combination therapy in recurrent, platinum-refractory, epithelial ovarian carcinoma: A retrospective analysis.

The study was undertaken to determine the safety and efficacy of the monoclonal, antivascular endothelial growth factor antibody bevacizumab in combination with cytotoxic chemotherapy for women with platinum‐refractory ovarian cancer.

Utility of parametrectomy for early stage cervical cancer treated with radical hysterectomy

Removal of the parametrial soft tissue is recommended for patients with cervical cancer undergoing radical hysterectomy. Parametrectomy results in significant morbidity. The objective of the study was to determine factors predictive of parametrial tumor spread and to define a subset of patients at low risk for parametrial disease.

Microsatellite Instability and Epigenetic Inactivation of MLH1 and Outcome of Patients With Endometrial Carcinomas of the Endometrioid Type

PURPOSE Most studies of microsatellite instability (MSI) and outcomes in endometrial cancer patients have included varied histologic subtypes. Nonetheless, MSI occurs almost exclusively in endometrioid tumors. The impact of MSI on outcomes in patients with endometrial cancer is controversial. We sought to determine whether MSI and MLH1 methylation are associated with clinicopathologic variables and survival outcomes in a large series of patients with endometrial carcinomas of the endometrioid type. PATIENTS AND METHODS Tumor samples, blood, and clinicopathologic data were prospectively collected and analyzed for 446 patients with endometrioid carcinomas. MSI was determined using five National Cancer Institute (NCI) consensus panel markers, and the methylation status of the MLH1 promoter was determined by combined bisulfite restriction analysis (COBRA). Associations with clinicopathologic variables and survival outcomes were evaluated. RESULTS MSI was identified in 147 cases (33%). MSI was associated with higher International Federation of Gynecology and Obstetrics (FIGO) grade (P < .0001). MSI+ tumors without MLH1 methylation were associated with younger age (P < .001). MSI was not associated with overall survival (OS; hazard ratio [HR], 1.011; 95% CI, 0.688 to 1.484; P = .96) or disease-free survival (DFS; HR 0.951; 95% CI, 0.554 to 1.635; P = .86). The combined MSI/MLH1 methylation status (treating MSI- as the reference) did not predict OS (MSI+/MLH1-U: HR, 0.62; 95% CI, 0.27 to 1.44; P = .26; MSI+/MLH1-M: HR, 0.95; 95% CI, 0.62 to 1.46; P = .82) or DFS (MSI+/MLH1-U: HR, 0.51; 95% CI, 0.22 to 1.19; P = .12; MSI+/MLH1-M: HR, 0.93; 95% CI, 0.62 to 1.40; P = .72). CONCLUSION MSI is not associated with survival in patients with endometrioid endometrial cancer.

Society of Gynecologic Oncology recommendations for the prevention of ovarian cancer

Mortality from ovarian cancer may be dramatically reduced with the implementation of attainable prevention strategies. The new understanding of the cells of origin and the molecular etiology of ovarian cancer warrants a strong recommendation to the public and health care providers. This document discusses potential prevention strategies, which include 1) oral contraceptive use, 2) tubal sterilization, 3) risk‐reducing salpingo‐oophorectomy in women at high hereditary risk of breast and ovarian cancer, 4) genetic counseling and testing for women with ovarian cancer and other high‐risk families, and 5) salpingectomy after childbearing is complete (at the time of elective pelvic surgeries, at the time of hysterectomy, and as an alternative to tubal ligation). The Society of Gynecologic Oncology has determined that recent scientific breakthroughs warrant a new summary of the progress toward the prevention of ovarian cancer. This review is intended to emphasize the importance of the fallopian tubes as a potential source of high‐grade serous cancer in women with and without known genetic mutations in addition to the use of oral contraceptive pills to reduce the risk of ovarian cancer. Cancer 2015;121:2108–2120.

Cervical dysplasia in adolescents.

Background: Although the incidence of cervical dysplasia in adolescents is increasing, a paucity of data exists regarding the outcomes of adolescents with Pap test abnormalities. We determined the natural history and outcome of adolescents with low-grade squamous intraepithelial lesions (LSIL) and high-grade squamous intraepithelial lesions (HSIL). Methods: A review of all women aged 18 years or younger with a cytologic diagnosis of LSIL or HSIL between 1997 and 2003 was performed. Follow-up cytologic and histologic samples were evaluated. The most significant abnormality was recorded for each patient. Rates of regression, persistence, and progression were calculated. Results: A total of 646 adolescents were identified. Follow-up was available for 477 teenagers with LSIL and for 55 with HSIL. Among adolescents with LSIL, 146 (35%) had negative follow-up. Low-grade abnormalities (atypical squamous cells of undetermined significance, LSIL, and cervical intraepithelial neoplasia grade 1) were seen in 199 (47%), whereas high-grade abnormalities were documented in 77 (18%). After 36 months, 62% had regressed, whereas 31% had progressive dysplasia. For the HSIL cohort, negative follow-up was documented in 12 (21.8%) adolescents, and 15 (27.3%) had low-grade abnormalities, whereas more than one half (50.9%) were found to have a high-grade abnormality. At 36 months, 31% of HSIL subjects had progressed to cervical intraepithelial neoplasia 3. Conclusion: Adolescents with LSIL and HSIL cytology are at significant risk for progression to high-grade cervical abnormalities. The rate of development of high-grade cervical abnormalities in adolescents is similar to adults. Adolescents with cytologic abnormalities mandate close follow-up. Level of Evidence: II-3

Penetrance and Expressivity of MSH6 Germline Mutations in Seven Kindreds Not Ascertained by Family History

Hereditary nonpolyposis colorectal cancer (HNPCC) is caused by inherited mutations in DNA mismatch-repair genes, most commonly MLH1 or MSH2. The role MSH6 plays in inherited cancer susceptibility is less well defined. The aim of this study was to investigate the penetrance and expressivity of MSH6 mutations in kindreds ascertained through endometrial cancer probands unselected for family history. Detailed pedigrees were constructed for six MSH6 mutation carriers. All reported cancers and precancers were confirmed, and tissues were obtained when available. Tumors were analyzed for microsatellite instability (MSI) and for expression of MSH2, MLH1, and MSH6. MSH6 mutation status was determined for 59 family members. Of these 59 individuals, 19 (32%) had confirmed cancers and precancers. There was an excess of mutation carriers among the 19 affected family members (11 [58%] of 19) compared with those among the 40 unaffecteds (8 [20%] of 40, P=.0065, odds ratio = 5.5, 95% CI = 1.66-18.19). In four of the seven tumors analyzed from mutation carriers other than the probands, MSI and/or MMR protein expression was consistent with the involvement of MSH6. Overall estimated penetrance of the MHS6 mutations was 57.7%. Of the tumors in mutation carriers, 78% were part of the extended HNPCC spectrum. This study demonstrates that MSH6 germline mutations are, indeed, associated with increased cancer risk and that the penetrance of mutations may be higher than appreciated elsewhere. A combination of MSI and immunohistochemistry analyses may be helpful in screening for MSH6 mutation carriers.

ATR mutation in endometrioid endometrial cancer is associated with poor clinical outcomes.

PURPOSE Mutations in the DNA damage response gene ATR (exon 10 A10 mononucleotide repeat) have been previously described in endometrial and other cancers with defective DNA mismatch repair. In vitro studies showed that endometrial cancer cell lines with A10 repeat tract truncating mutations have a failure in the ATR-dependent DNA damage response. Cell lines carrying A10 mutations fail to trigger Chk1 activation in response to ionizing radiation and topoisomerase inhibitors. We sought to determine the frequency and clinicopathologic significance of ATR mutations in patients with endometrioid endometrial cancer. PATIENTS AND METHODS The ATR exon 10 A10 repeat was analyzed by direct sequencing in 141 tumors with microsatellite instability (MSI-positive) and 107 microsatellite stable (MSI-negative) tumors. The relationships between mutations and clinicopathologic variables, including overall and disease-free survival, were assessed using contingency table tests and Cox proportional hazard models. Results ATR mutations were identified in 12 cases (4.8%; three cases with insertions and nine cases with deletions). Mutations occurred exclusively in MSI-positive tumors (P = .02), with an overall mutation rate of 8.5%. Mutation was not associated with age, race, surgical stage, International Federation of Gynecology and Obstetrics grade, or adjuvant treatment. Multivariate analyses revealed a significant association with reduced overall survival (hazard ratio [HR] = 3.88; 95% CI, 1.64 to 9.18; P = .002) and disease-free survival (HR = 4.29; 95% CI, 1.48 to 12.45; P = .007). CONCLUSION Truncating ATR mutations in endometrial cancers are associated with biologic aggressiveness as evidenced by reduced disease-free and overall survival. Knowledge of ATR mutation status may hold promise for individualized treatment and targeted therapies in patients with endometrial cancer.

A multi‐institutional evaluation of factors predictive of toxicity and efficacy of bevacizumab for recurrent ovarian cancer

While bevacizumab has shown activity in recurrent ovarian cancer, a higher than expected incidence of bowel perforations has been reported in recent trials. We sought to determine factors associated with toxicity and tumor response in patients with relapsed ovarian cancer treated with bevacizumab. A retrospective review of patients with recurrent ovarian cancer treated with bevacizumab was undertaken. Response was determined radiographically and through CA125 measurements. Statistical analysis to determine factors associated with toxicity and response was performed. Sixty-two eligible patients were identified. The cohort had received a median of 5 prior chemotherapy regimens. Single-agent bevacizumab was administered to 12 (19%), while 50 (81%) received the drug in combination with a cytotoxic agent. Grade 3–5 toxicities occurred in 15 (24%) patients, including grade 3–4 hypertension in 4 (7%), gastrointestinal perforations in 7%, and chylous ascites in 5%. Development of chylous ascites and gastrointestinal perforations appeared to correlate with tumor response. The overall response rate was 36% (4 complete response, 17 partial response), with stable disease in 40%. A higher objective response rate was seen in the bevacizumab combination group compared to single-agent treatment (43% vs 10%) (P = 0.07). However, 29 grade 3–5 toxic episodes were seen in the combination group vs only 1 in the single-agent bevacizumab cohort (P = 0.071). We conclude that bevacizumab demonstrates promising activity in recurrent ovarian cancer. The addition of a cytotoxic agent to bevacizumab improved response rates at the cost of increased toxicity. Gastrointestinal perforations occurred in 7%. The perforations occurred in heavily pretreated patients who were responding to therapy

Increased Risk for Hereditary Nonpolyposis Colorectal Cancer-Associated Synchronous and Metachronous Malignancies in Patients with Microsatellite Instability-Positive Endometrial Carcinoma Lacking MLH1 Promoter Methylation

Purpose: The aim of this study was to evaluate number and types of synchronous and metachronous malignancies in patients with endometrial carcinoma with and without microsatellite instability (MSI). Experimental Design: From a series of 413 endometrial cancer patients, we identified 94 patients with MSI-positive (MSI+) cancers and grouped them by tumor MLH1 promoter methylation status. These 94 patients were matched by year of surgery to 94 patients with MSI-negative (MSI−) endometrial cancers from the same series. Medical records were reviewed for clinicopathologic information including rates and types of synchronous and metachronous malignancies. Hereditary nonpolyposis colorectal cancer (HNPCC)-associated second and third cancers were analyzed for MSI and MSH2, MSH6, and MLH1 expression for comparison with the corresponding endometrial cancers. Results: The MSI+ and MSI− cohorts were similar with regard to age, race, grade, and histology. Twenty-eight MSI+ endometrial cancers (29.8%) were MLH1 unmethylated. Rates of synchronous and metachronous cancers were also similar in the MSI+ and MSI− groups at 20 and 23%, respectively. However, patients with MSI+ MLH1 unmethylated endometrial cancers had an excess of HNPCC-associated second and third cancers compared with those with MSI+ MLH1 methylated and MSI− endometrial cancers (18% versus 4.5%, P = 0.034, and 2.1%, P = 0.002). Six of seven second tumors from 5 patients with MSI+ MLH1 unmethylated endometrial cancers showed concordant MSI and mismatch repair protein expression status. Conclusions: Our observation that patients with MSI-positive MLH1 unmethylated endometrial carcinoma are at increased risk for HNPCC-associated synchronous and metachronous malignancies suggests inherited cancer susceptibility. These patients and their families may warrant more intense cancer surveillance.