Sheri A. Babb

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.

MSI in endometrial carcinoma: Absence of MLH1 promoter methylation is associated with increased familial risk for cancers

Loss of DNA mismatch repair occurs in a variety of malignancies and is associated with genome‐wide instability of microsatellite repeats, a molecular phenotype referred to as microsatellite instability (MSI). MSI is a consistent feature of colorectal and endometrial tumors from patients with hereditary non‐polyposis colorectal cancer (HNPCC). Sporadic colorectal and endometrial cancers that exhibit MSI frequently have methylation of the MLH1 promoter. We undertook a detailed family and medical history study to compare family cancer risk for women with MSI‐positive and ‐negative endometrial cancers. The MLH1 promoter methylation status was determined for all cancers. Family histories were developed for 80 probands (40 with MSI‐positive and 40 with MSI‐negative tumors). The numbers of reported cancers in first‐ and second‐degree relatives of the 2 groups were similar. There was a modest increase in familial cancer clustering for MSI‐positive probands. When MSI‐positive tumors were subclassified according to MLH1 promoter methylation, a clear association between methylation status and familial cancer risk was evident. Women with MSI‐positive endometrial cancers in which the MLH1 promoter was unmethylated had a 7‐fold relative risk (RR) of demonstrating familial clustering of cancers [RR 7.07 (95% confidence interval 2.29–21.81)]. The women with MSI‐positive, MLH1‐unmethylated tumors were significantly younger than the rest of the study population (56.1 years vs. 65.4, p ≤ 0.01). Age of onset and tumor MSI not associated with MLH1 promoter methylation may point to women with a genetic susceptibility to malignancies.

Qualitative Evaluation of Medical Information Processing Needs of 60 Women Choosing Ovarian Cancer Surveillance or Prophylactic Oophorectomy

Thirty women who had prophylactic oophorectomy (PO) and thirty women undergoing ovarian cancer surveillance (OCS) completed a one-time in-depth telephone interview exploring information gathering and decision-making processes. There were close similarities between groups, including age, race, marital status, education, menopausal status, number undergoing genetic testing for BRCA mutations, and number of prophylactic mastectomies. The majority of participants indicated overall satisfaction with their final decision. However, many described the information gathering process as frustrating and anxiety provoking. Participants in both groups expressed a need to process medical information within the context of individual psychosocial needs and personal perceptions and experiences. There were recurrent themes with regard to informational and psychosocial needs and personal perceptions and experiences that impacted decision-making process for these women. The present paper is a companion paper to Swisher et al. (J Repr Med 2001, 46:87–94) with the focus of this paper to illustrate the medical informational processing needs identified by this group of women.

Underestimation of risk of a BRCA1 or BRCA2 mutation in women with high-grade serous ovarian cancer by BRCAPRO: a multi-institution study.

PURPOSE Identification of the 10% to 15% of patients with ovarian cancer who have germline BRCA1 or BRCA2 mutations is important for management of both patients and relatives. The BRCAPRO model, which estimates mutation likelihood based on personal and family cancer history, can inform genetic testing decisions. This studys purpose was to assess the accuracy of BRCAPRO in women with ovarian cancer. METHODS BRCAPRO scores were calculated for 589 patients with ovarian cancer referred for genetic counseling at three institutions. Observed mutations were compared with those predicted by BRCAPRO. Analysis of variance was used to assess factors impacting BRCAPRO accuracy. RESULTS One hundred eighty (31%) of 589 patients with ovarian cancer tested positive. At BRCAPRO scores less than 40%, more mutations were observed than expected (93 mutations observed v 34.1 mutations expected; P < .001). If patients with BRCAPRO scores less than 10% had not been tested, 51 (28%) of 180 mutations would have been missed. BRCAPRO underestimated the risk for high-grade serous ovarian cancers but overestimated the risk for other histologies (P < .001), underestimation increased as age at diagnosis decreased (P = .02), and model performance varied by institution (P = .02). CONCLUSION Patients with ovarian cancer classified as low risk by BRCAPRO are more likely to test positive than predicted. The risk of a mutation in patients with low BRCAPRO scores is high enough to warrant genetic testing. This study demonstrates that assessment of family history by a validated model cannot effectively target testing to a high-risk ovarian cancer patient population, which strongly supports the recommendation to offer BRCA1/BRCA2 genetic testing to all patients with high-grade serous ovarian cancer regardless of family history.

Epitope-positive truncating MLH1 mutation and loss of PMS2: implications for IHC-directed genetic testing for lynch syndrome

We assessed mismatch repair by immunohistochemistry (IHC) and microsatellite instability (MSI) analysis in an early onset endometrial cancer and a sister’s colon cancer. We demonstrated high-level MSI and normal expression for MLH1, MSH2 and MSH6. PMS2 failed to stain in both tumors, strongly implicating a PMS2 defect. This family did not meet clinical criteria for Lynch syndrome. However, early onset endometrial cancers in the proband and her sister, a metachronous colorectal cancer in the sister as well as MSI in endometrial and colonic tumors suggested a heritable mismatch repair defect. PCR-based direct exonic sequencing and multiplex ligation-dependent probe amplification (MLPA) were undertaken to search for PMS2 mutations in the germline DNA from the proband and her sister. No mutation was identified in the PMS2 gene. However, PMS2 exons 3, 4, 13, 14, 15 were not evaluated by MLPA and as such, rearrangements involving those exons cannot be excluded. Clinical testing for MLH1 and MSH2 mutation revealed a germline deletion of MLH1 exons 14 and 15. This MLH1 germline deletion leads to an immunodetectable stable C-terminal truncated MLH1 protein which based on the IHC staining must abrogate PMS2 stabilization. To the best of our knowledge, loss of PMS2 in MLH1 truncating mutation carriers that express MLH1 in their tumors has not been previously reported. This family points to a potential limitation of IHC-directed gene testing for suspected Lynch syndrome and the need to consider comprehensive MLH1 testing for individuals whose tumors lack PMS2 but for whom PMS2 mutations are not identified.

Impact of an immunohistochemistry-based universal screening protocol for Lynch syndrome in endometrial cancer on genetic counseling and testing

OBJECTIVE Evaluate effects of a Lynch syndrome universal screening protocol in newly diagnosed endometrial cancers on subsequent genetic counseling (GC) and germline testing (GT) referral and acceptance rates. METHODS We performed a retrospective cohort study of women who underwent a hysterectomy for endometrial cancer at Barnes Jewish Hospital in St. Louis, MO between 1/1/2011 and 12/31/2013 (n=637). An immunohistochemistry-based (IHC) universal screening protocol for Lynch syndrome was initiated on 12/17/2012. The cohorts consisted of women presenting prior to (Pre-Em-USP; n=395) and those presenting following (Em-USP; n=242) initiation of the universal screening protocol. GC and GT referrals were based on risk factors and/or IHC results. Comparisons were made using the Fishers exact test and the Kruskal-Wallis test. RESULTS A greater proportion of individuals in the Em-USP cohort underwent GT than in Pre-Em-USP (9.1% vs 4.8%, p<0.05). Of individuals with an IHC screening result suggestive of LS, those within the Em-USP cohort were significantly more likely to accept GC compared to those in the Pre-Em-USP cohort (95% vs 64%, p=0.02). Specifically within the Em-USP cohort, patients referred to GC due to a concerning IHC screening result, versus those who were referred based on other risk factors, had a higher counseling acceptance rate (95% vs 61%, p=0.03) and underwent genetic testing more readily (76% vs 30%, p<0.001). CONCLUSIONS Implementation of an IHC-based universal screening protocol for LS in endometrial cancer leads to higher acceptance of genetic counseling and higher rates of genetic testing compared to referral based on risk factors alone.

Cancer among first-degree relatives of probands with invasive and borderline ovarian cancer.

Objective The familial clustering of ovarian, breast, endometrial, colon, and prostate cancer was compared in firstdegree relatives of probands with invasive and borderline ovarian cancer to determine coaggregation. Methods Probands (n = 392), who had been patients in the Division of Gynecologic Oncology at Washington University, were ascertained consecutively. Family history on 2192 first-degree relatives was collected by personal interviews of the probands and other family members. Estimates of prevalence of cancers in first-degree relatives of the two proband groups were compared. Survival analysis was used to examine the age-at-onset distribution of each cancer in relatives of invasive probands versus relatives of borderline probands. Results Among the relatives were 24 cases of ovarian cancer, 46 cases of breast cancer, 13 cases of endometrial cancer, and 25 and 28 cases of colon and prostate cancer, respectively. There were no significant differences in the prevalence of any of these cancers in relatives of the invasive and borderline probands. Cumulative lifetime risk estimates did not differ between the relatives of the two groups for any cancers. Age-at-onset of ovarian cancer did not differ between probands with positive family histories of the five cancers and those with negative histories. The inability to reject the null hypothesis of no differences in the first-degree relatives of our two study groups might be from insufficient power to detect small differences, given our sample size. Conclusion These results suggest that relatives of patients with invasive and borderline ovarian cancer might share similar cancer risks and age-at-onset distributions.

Timing of referral for genetic counseling and genetic testing in patients with ovarian, fallopian tube, or primary peritoneal carcinoma.

Objective The objective of this study was to assess patients’ preferences of the timing of referral for genetic counseling and testing in relation to the diagnosis, treatment, and recurrence of ovarian, tubal, or primary peritoneal cancers. Methods Ninety-two patients who underwent counseling and testing by 1 certified genetic counselor were identified. An introductory letter, consent form, and questionnaire were mailed to gather information regarding factors influencing the decision to undergo genetic counseling and testing and opinions regarding optimal timing. Medical records were reviewed for demographic and clinical data. Results Of 47 consenting women, 45 underwent testing. Eight (18%) were found to have a genetic mutation. Women lacked consensus about the optimal time for referral for and to undergo genetic testing, although women with stage I disease preferred testing after completion of chemotherapy. Most women were comfortable receiving the results by phone, but one third preferred an office visit. Conclusions Patients’ views regarding the best time to be referred for and undergo counseling and testing varied greatly. Because of the high mortality of this disease, clinicians should discuss referral early and personalize the timing to each patient. The subset of patients who prefer results disclosure during an office visit should be identified at the time of their initial counseling.

Endometrial adenosarcoma in the setting of a germline DICER1 mutation: A case report☆

Highlights • DICER1 mutations play a significant role in gynecologic malignancy.• DICER1 may be involved in the sarcomagenesis of endometrial adenosarcoma.• The knowledge of a genetic mutation can help clarify a patients medical history.