Endometrial Cancer in a Family With RAD51D Gene Mutation.

RAD51 complex plays an important role in homologous recombination deficiency and germline mutations have a well-documented association with breast and tubo-ovarian carcinoma, as well as serous-type endometrial carcinoma. We report a family of French Canadian ancestry with a germline mutation in RAD51D and two sisters presenting with endometrial carcinoma, endometrioid-type. The risk factors for endometrial adenocarcinoma, endometrioid-type are discussed in the context of the RAD51-associated carcinomas described to date.

Serous Tubal Intraepithelial Carcinoma in a Risk-reducing Salpingo-oophorectomy Specimen From a RAD51D Mutation Carrier: A Case Report.

The RAD51D gene codes a protein-paralog of the RAD51 DNA recombinase, which catalyzes DNA strand exchange during homologous recombination. Similar to BRCA1 / BRCA2 , mutations in RAD51D both predispose to ovarian carcinoma and impart sensitivity to poly (ADP-ribose) polymerase inhibitors in preclinical studies. Based on cancer risk prediction models, RAD51D mutations pose a moderate-to-high risk for ovarian cancer warranting consideration for risk-reducing surgery. We report a case of serous tubal intraepithelial carcinoma in a patient undergoing risk-reducing total hysterectomy with bilateral salpingo-oophorectomy for a RAD51D pathogenic variant. The histopathologic and p53-immunophenotypic features of this lesion are similar to those reported previously in BRCA1 / BRCA2 mutation carriers and those of serous tubal intraepithelial carcinoma associated with sporadic high-grade serous carcinomas. These features include marked increase in nuclear-to-cytoplasmic ratio, loss of cell polarity, absence of ciliation, prominent nucleoli, mitotic activity, epithelial stratification, surface exfoliative changes, and complete loss of p53 staining. Although familial ovarian cancers with mutations in RAD51D -or other genes in the Fanconi anemia pathway-are much less common those with BRCA1 / BRCA2 mutations, our findings support a common phenotype for early serous cancers in this pathway.

The risks of breast and ovarian cancer associated with the Ashkenazi Jewish founder allele BRCA2 6174delT.

Approximately 1% of the Ashkenazi Jewish population carries the BRCA2 6174delT (c.5946del) pathogenic variant. It is important to have accurate knowledge of the risks of breast and ovarian cancer associated with this specific variant so that women may be counseled accordingly. In this prospective study, we estimated the risks of breast and ovarian cancer associated with the 6174delT variant compared with the risks for other pathogenic variants in the BRCA2 gene. The annual risk for developing breast cancer was significantly lower in 246 women who carried the 6174delT variant compared with 721 non-Jewish women who carried a variant at any other locus in BRCA2 (1.2% per year vs. 2.4% per year, p = 0.003). We estimated the cumulative risk of breast cancer from age 30 to 70 to be 39% for carriers of the BRCA2 6174delT variant and 61% for carriers of other BRCA2 variants. The annual risk for ovarian or fallopian tube cancer was 0.51% per year for the 233 women who carried the 6174delT variant compared to 0.22% per year for the 1128 carriers of other BRCA2 variants; the difference was not significant. Lower risks for breast cancer associated with 6174delT may not impact screening and prevention choices, however, the discussion should be based on accurate risk assessment.

An evaluation of memory and attention in BRCA mutation carriers using an online cognitive assessment tool.

BACKGROUND: The objective of this study was to evaluate the impact of various surgical, hormonal, and lifestyle factors on memory and attention in women with a BRCA1 or BRCA2 mutation. METHODS: BRCA mutation carriers enrolled in a longitudinal study were invited to complete an online brain health assessment tool designed to screen for cognitive deficits. Four measures of memory and executive attention were assessed individually, and an overall score was compiled adjusting for age. Exposures, including preventive surgery, hormone use, and lifestyle factors, were captured by questionnaire. Performance on each of the 5 subtasks was analyzed according to various exposures. Analysis of covariance was used to compare overall scores. RESULTS: In total, 880 women completed the online cognitive assessment. The average age of the participants was 54 years (range, 23-86 years). The mean overall test score was 54.4 (range, 0-93). The individual subtask scores declined with age at test completion (P < .0001) and increased with level of education (P ≤ .01). Women who underwent a preventive oophorectomy had a significantly higher overall score compared with women who did not undergo this surgery (55.5 vs 50.5; P = .01). Reconstructive breast surgery was also associated with a higher overall score (56.5 vs 52.3; P = .005). Chemotherapy and hormone-replacement therapy were not predictive of the overall score. CONCLUSIONS: These findings are reassuring to high-risk women who undergo early surgical menopause for their cancer predisposition. Further studies are needed to evaluate cognitive function over time when memory deficits become more prevalent.

Risk for breast cancer and management of unaffected individuals with non-BRCA hereditary breast cancer.

About 5%-10% of breast cancer is hereditary with BRCA1 and BRCA2 being the most common genes associated with hereditary breast cancer (HBC). Several additional genes have recently been associated with HBC. These genes can be classified as highly or moderately penetrant genes with lifetime risk >30% or 17%-30%, respectively. Highly penetrant genes associated with HBC include TP53, PTEN, CDH1, STK11, and PALB2. While, moderately penetrant genes include CHEK2, ATM, BARD1, BRIP1, NBN, NF1, RAD51D, and MSH6. Breast cancer risk and recommendations for screening and risk-reduction vary by gene. In general, screening breast MRI is recommended for women at >20% lifetime risk, which includes women with mutations in highly penetrant genes and the majority (but not all) moderately penetrant genes. Consideration of chemoprevention is recommended for women with mutations in high and moderately penetrant genes. Risk-reducing mastectomy does reduce the risk of breast cancer to the greatest extent and can be considered for women with highly penetrant genes. However, this procedure is associated with significant morbidities that should be considered, especially given the benefit of using screening breast MRI for high-risk women. BSO is only recommended for women with mutations in genes associate with increased risk for ovarian cancer and not as a breast cancer risk-reducing strategy. As more women undergo testing, additional genes may be identified and risk estimates for current genes and management recommendations may be modified.

Thorough in silico and in vitro cDNA analysis of 21 putative BRCA1 and BRCA2 splice variants and a complex tandem duplication in BRCA2 allowing the identification of activated cryptic splice donor sites in BRCA2 exon 11.

For 21 putative BRCA1 and BRCA2 splice site variants, the concordance between mRNA analysis and predictions by in silico programs was evaluated. Aberrant splicing was confirmed for 12 alterations. In silico prediction tools were helpful to determine for which variants cDNA analysis is warranted, however, predictions for variants in the Cartegni consensus region but outside the canonical sites, were less reliable. Learning algorithms like Adaboost and Random Forest outperformed the classical tools. Further validations are warranted prior to implementation of these novel tools in clinical settings. Additionally, we report here for the first time activated cryptic donor sites in the large exon 11 of BRCA2 by evaluating the effect at the cDNA level of a novel tandem duplication (5' breakpoint in intron 4; 3' breakpoint in exon 11) and of a variant disrupting the splice donor site of exon 11 (c.6841+1G > C). Additional sites were predicted, but not activated. These sites warrant further research to increase our knowledge on cis and trans acting factors involved in the conservation of correct transcription of this large exon. This may contribute to adequate design of ASOs (antisense oligonucleotides), an emerging therapy to render cancer cells sensitive to PARP inhibitor and platinum therapies.

Universal Versus Targeted Screening for Lynch Syndrome: Comparing Ascertainment and Costs Based on Clinical Experience.

BACKGROUND: Strategies to screen colorectal cancers (CRCs) for Lynch syndrome are evolving rapidly; the optimal strategy remains uncertain. AIM: We compared targeted versus universal screening of CRCs for Lynch syndrome. METHODS: In 2010-2011, we employed targeted screening (age < 60 and/or Bethesda criteria). From 2012 to 2014, we screened all CRCs. Immunohistochemistry for the four mismatch repair proteins was done in all cases, followed by other diagnostic studies as indicated. We modeled the diagnostic costs of detecting Lynch syndrome and estimated the 5-year costs of preventing CRC by colonoscopy screening, using a system dynamics model. RESULTS: Using targeted screening, 51/175 (29 %) cancers fit criteria and were tested by immunohistochemistry; 15/51 (29 %, or 8.6 % of all CRCs) showed suspicious loss of ≥1 mismatch repair protein. Germline mismatch repair gene mutations were found in 4/4 cases sequenced (11 suspected cases did not have germline testing). Using universal screening, 17/292 (5.8 %) screened cancers had abnormal immunohistochemistry suspicious for Lynch syndrome. Germline mismatch repair mutations were found in only 3/10 cases sequenced (7 suspected cases did not have germline testing). The mean cost to identify Lynch syndrome probands was ~$23,333/case for targeted screening and ~$175,916/case for universal screening at our institution. Estimated costs to identify and screen probands and relatives were: targeted, $9798/case and universal, $38,452/case. CONCLUSIONS: In real-world Lynch syndrome management, incomplete clinical follow-up was the major barrier to do genetic testing. Targeted screening costs 2- to 7.5-fold less than universal and rarely misses Lynch syndrome cases. Future changes in testing costs will likely change the optimal algorithm.

Patient Perceptions of Telephone vs. In-Person BRCA1/BRCA2 Genetic Counseling.

Telephone genetic counseling (TC) for hereditary breast/ovarian cancer risk has been associated with positive outcomes in high risk women. However, little is known about how patients perceive TC. As part of a randomized trial of TC versus usual care (UC; in-person genetic counseling), we compared high risk women's perceptions of: (1) overall satisfaction with genetic counseling; (2) convenience; (3) attentiveness during the session; (4) counselor effectiveness in providing support; and (5) counselor ability to recognize emotional responses during the session. Among the 554 participants (TC, N = 272; UC, N = 282), delivery mode was not associated with self-reported satisfaction. However, TC participants found counseling significantly more convenient than UC participants (OR = 4.78, 95 % CI = 3.32, 6.89) while also perceiving lower levels of support (OR = 0.56, 95 % CI = 0.40-0.80) and emotional recognition (OR = 0.53, 95 % CI = 0.37-0.76). In exploratory analyses, we found that non-Hispanic white participants reported higher counselor support in UC than in TC (69.4 % vs. 52.8 %; OR = 3.06, 95 % CI = 1.39-6.74), while minority women perceived less support in UC vs. TC (58.3 % vs. 38.7 %; OR = 0.80, 95 % CI = 0.39-1.65). We discuss potential research and practice implications of these findings which may further improve the effectiveness and utilization of TC.

Effect of Sulindac and Erlotinib vs Placebo on Duodenal Neoplasia in Familial Adenomatous Polyposis: A Randomized Clinical Trial.

IMPORTANCE: Patients with familial adenomatous polyposis (FAP) are at markedly increased risk for duodenal polyps and cancer. Surgical and endoscopic management of duodenal neoplasia is difficult and chemoprevention has not been successful. OBJECTIVE: To evaluate the effect of a combination of sulindac and erlotinib on duodenal adenoma regression in patients with FAP. DESIGN, SETTING, AND PARTICIPANTS: Double-blind, randomized, placebo-controlled trial, enrolling 92 participants with FAP, conducted from July 2010 through June 2014 at Huntsman Cancer Institute in Salt Lake City, Utah. INTERVENTIONS: Participants with FAP were randomized to sulindac (150 mg) twice daily and erlotinib (75 mg) daily (n = 46) vs placebo (n = 46) for 6 months. MAIN OUTCOMES AND MEASURES: The total number and diameter of polyps in the proximal duodenum were mapped at baseline and 6 months. The primary outcome was change in total polyp burden at 6 months. Polyp burden was calculated as the sum of the diameters of polyps. The secondary outcomes were change in total duodenal polyp count, change in duodenal polyp burden or count stratified by genotype and initial polyp burden, and percentage of change from baseline in duodenal polyp burden. RESULTS: Ninety-two participants (mean age, 41 years [range, 24-55]; women, 56 [61%]) were randomized when the trial was stopped by the external data and safety monitoring board because the second preplanned interim analysis met the prespecified stopping rule for superiority. Grade 1 and 2 adverse events were more common in the sulindac-erlotinib group, with an acne-like rash observed in 87% of participants receiving treatment and 20% of participants receiving placebo (P < .001). Only 2 participants experienced grade 3 adverse events. [table: see text]. CONCLUSIONS AND RELEVANCE: Among participants with FAP, the use of sulindac and erlotinib compared with placebo resulted in a lower duodenal polyp burden after 6 months. Adverse events may limit the use of these medications at the doses used in this study. Further research is necessary to evaluate these preliminary findings in a larger study population with longer follow-up to determine whether the observed effects will result in improved clinical outcomes. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT 01187901.

Disparities in uptake of BRCA1/2 genetic testing in a randomized trial of telephone counseling.

PURPOSE: As genetic counseling and testing become more fully integrated into clinical care, alternative delivery models are increasingly prominent. This study examines predictors of genetic testing for hereditary breast/ovarian cancer among high-risk women in a randomized trial of in-person versus telephone-based genetic counseling. METHODS: Methods include multivariable logistic regression and interaction analyses. RESULTS: Of the 669 participants, 600 completed counseling and 523 received test results. As previously reported, participants randomized to telephone counseling were significantly less likely to be tested. In intention-to-treat analyses, completion of counseling and testing was associated with: race/ethnicity (odds ratio (OR) = 1.96, 95% confidence interval (CI): 1.20-3.20), perceived stress (OR = 0.89, 95% CI: 0.81-0.98), knowledge (OR = 1.12, 95% CI: 1.02-1.23), and randomization group (OR = 1.48, 95% CI: 1.01-2.16). Further, race/ethnicity moderated the association between randomization group and testing; minority women receiving telephone counseling were least likely to complete testing. CONCLUSION: Evidence for logistical and communication-based explanations for this interaction is presented. The overall increased access made possible with telephone genetic counseling should be considered in light of the possibility that this may also lead to lower rates of testing among high-risk minority women. Additional care should be taken to assess and address potential barriers when services are delivered by telephone.Genet Med 17 6, 467-475.

Intentions for risk-reducing surgery among high-risk women referred for BRCA1/BRCA2 genetic counseling.

OBJECTIVE: Genetic testing for breast and ovarian cancer susceptibility is now part of routine clinical practice. Although rates of risk-reducing surgery following genetic testing have been increasing, little is known about attitudes toward risk-reducing surgery in women prior to genetic counseling and testing. This study examines correlates of patient intentions to undergo risk-reducing mastectomy (RRM) and risk-reducing oophorectomy (RRO). METHODS: Participants were 696 women, ages 21-85, who sought breast cancer gene 1 and 2 (BRCA1/2) genetic counseling and had at least a 10% risk of carrying a mutation. The sample included women who were affected with breast or ovarian cancer and unaffected women with a known familial BRCA1/2 mutation. Participants completed a precounseling telephone questionnaire. RESULTS: Prior to receiving genetic counseling, 23.3% of participants were considering RRM and 42.5% were considering RRO. Variables that were independently associated with RRM intentions were cancer-specific distress (OR = 1.14, 95% CI = 1.03-1.26), perceived risk of breast cancer (OR = 1.16, 95% CI = 1.05-1.28), education (OR = 1.76, 95% CI = 1.03-2.99), and age (OR = 0.96, 95% CI = 0.95-0.98). Predictors of RRO intentions were perceived risk for ovarian cancer (OR = 1.25, 95% CI = 1.14-1.37), perceived risk of carrying a BRCA1/2 mutation (OR = 1.74, 95% CI = 1.15-2.62), marital status (OR = 1.92, 95% CI = 1.34-2.76), and age (OR = 1.02, 95% CI = 1.00-1.03). CONCLUSIONS: Because precounseling intentions predict subsequent risk-reducing surgery decisions, this study identified patient factors associated with surgical intentions. These factors reinforce the critical role for pretest genetic counseling in communicating accurate risk estimates and management options, and addressing psychosocial concerns, to facilitate informed decision making regarding RRM and RRO.

Familial multiple pilomatrixomas as a presentation of attenuated adenomatosis polyposis coli.

Pilomatrixomas are benign follicular tumors that occur most commonly in children. Rare multiple or familial pilomatrixomas have been associated with myotonic dystrophy and other disorders. Although sporadic pilomatrixomas and hybrid cutaneous cysts with pilomatrixoma-like features have been observed in some kindreds with Gardner syndrome, an autosomal dominant form of familial adenomatous polyposis, no definitive association has been made with multiple or familial pilomatrixomas. Here we describe two siblings with multiple pilomatrixomas who were also found to have a family history of colonic adenocarcinoma. Genetic testing revealed a mutation in the 5' portion of the adenomatous polyposis coli (APC) gene, in a region associated with an attenuated APC phenotype. These findings show that multiple pilomatrixomas may be the presenting symptom of patients with APC gene mutations.

Essential elements of genetic cancer risk assessment, counseling, and testing: updated recommendations of the National Society of Genetic Counselors.

Updated from their original publication in 2004, these cancer genetic counseling recommendations describe the medical, psychosocial, and ethical ramifications of counseling at-risk individuals through genetic cancer risk assessment with or without genetic testing. They were developed by members of the Practice Issues Subcommittee of the National Society of Genetic Counselors Familial Cancer Risk Counseling Special Interest Group. The information contained in this document is derived from extensive review of the current literature on cancer genetic risk assessment and counseling as well as the personal expertise of genetic counselors specializing in cancer genetics. The recommendations are intended to provide information about the process of genetic counseling and risk assessment for hereditary cancer disorders rather than specific information about individual syndromes. Essential components include the intake, cancer risk assessment, genetic testing for an inherited cancer syndrome, informed consent, disclosure of genetic test results, and psychosocial assessment. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. These recommendations do not displace a health care provider's professional judgment based on the clinical circumstances of a client.

Telephone versus in-person genetic counseling for hereditary cancer risk: Patient predictors of differential outcomes.

PURPOSE: Telegenetics has become the predominant mode of cancer genetic counseling during the COVID-19 pandemic. We sought to identify potential patient-level contraindicators for telegenetic genetic counseling. METHODS: We analyzed post-counseling (pre-result disclosure) follow-up data from a randomized noninferiority trial of a telephone genetic counseling versus usual care genetic counseling. Among 669 randomized participants, 600 completed pre-test counseling and 568 completed a 2-week follow-up assessment before receiving test results. In this analysis, we focused on genetic counseling outcomes (knowledge, decisional conflict, and distress). In multivariate models controlling for bivariate predictors of these outcomes, we tested our a priori hypotheses that pre-counseling numeracy, perceived stress, and race/ethnicity would moderate the outcomes of telephone genetic counseling versus usual care. RESULTS: Only numeracy significantly moderated associations between mode of genetic counseling and outcomes. Higher numeracy was associated with higher post-counseling knowledge following telephone genetic counseling (p < 0.001), but not usual care (p = 0.450). Higher numeracy was also associated with lower distress following telephone genetic counseling (p = 0.009) but not usual care (p = 0.16). Neither perceived stress nor race/ethnicity exhibited differential impacts on telephone genetic counseling versus usual care (ps > 0.20). CONCLUSION: Although high numeracy was associated with higher levels of knowledge following telegenetic counseling, we did not identify any clinically significant patient-level contraindicators for telegenetic counseling. These results lend further confidence to the broad use of telegenetics.

Acute Myeloid Leukemia with t(8;16)(p11.2;p13.3)/ KAT6A-CREBBP in a Patient with an NF1 Germline Mutation and Clinical Presentation Mimicking Acute Promyelocytic Leukemia.

OBJECTIVES: Acute myeloid leukemia (AML) with t(8;16)(p11.2;p13.3)/KAT6A-CREBBP is an uncommon subtype of AML accounting for less than 0.5% of AML cases. AML with t(8;16)/KAT6A-CREBBP has characteristic clinical and pathologic features including disseminated intravascular coagulation (DIC), leukemia cutis, hemophagocytosis, monocytic or myelomonocytic differentiation, is frequently associated with therapy-related AML and has a poor prognosis. We present a classic case of AML with t(8;16)/KAT6A-CREBBP occurring in a patient with both a germline NF1 mutation and recent cytotoxic therapy for embryonal rhabdomyosarcoma.

Rapid progression of prostate cancer in men with a BRCA2 mutation.

Men with BRCA2 mutations have been found to be at increased risk of developing prostate cancer. There is a recent report that BRCA2 carriers with prostate cancer have poorer survival than noncarrier prostate cancer patients. In this study, we compared survival of men with a BRCA2 mutation and prostate cancer with that of men with a BRCA1 mutation and prostate cancer. We obtained the age at diagnosis, age at death or current age from 182 men with prostate cancer from families with a BRCA2 mutation and from 119 men with prostate cancer from families with a BRCA1 mutation. The median survival from diagnosis was 4.0 years for men with a BRCA2 mutation vs 8.0 years for men with a BRCA1 mutation, and the difference was highly significant (P<0.01). It may be important to develop targeted chemotherapies to treat prostate cancer in men with a BRCA2 mutation.

Colorectal Carcinomas With Isolated Loss of PMS2 Staining by Immunohistochemistry.

CONTEXT: - Isolated loss of PMS2 staining is an uncommon immunophenotype in colorectal carcinomas, accounting for approximately 4% of tumors with microsatellite instability. Limited information regarding these tumors is available in the literature. OBJECTIVE: - To compare the clinicopathologic features of colorectal carcinomas with isolated PMS2 loss by immunohistochemistry to those with other forms of mismatch repair deficiency. DESIGN: - Ninety-three colorectal carcinomas with isolated PMS2 loss by immunohistochemistry and 193 with other forms of mismatch repair deficiency were identified. Forty (43%) of the isolated PMS2 loss cases and 35 control cases (18%) had a known germline mutation or a clinical diagnosis of Lynch syndrome. RESULTS: - Overall, isolated PMS2-loss tumors occurred in significantly younger patients ( P < .001) and in fewer female patients ( P = .006). These tumors were significantly less likely to be right-sided ( P = .001), high-grade ( P = .01), or display histologic features of microsatellite instability ( P < .001). The isolated PMS2-loss group also exhibited increased odds of disease-specific death (odds ratio [OR], 3.09; 95% CI, 1.41-6.85; P = .007). When the analysis was restricted to germline mutation/Lynch syndrome cases and controls, no significant differences were detected for age, sex, tumor location, tumor grade, histologic features, or distant metastases, although a trend toward increased odds of disease-specific death in the isolated PMS2-loss group was evident (OR, 3.87; 95% CI, 0.89-27.04; P = .10). CONCLUSIONS: - Unusual clinicopathologic features observed in colorectal carcinomas with isolated PMS2 loss are likely related to the high proportion of cases caused by germline mutations. Isolated PMS2-loss tumors may demonstrate more aggressive behavior than other tumors with microsatellite instability, but larger studies are needed to investigate that possibility further.

Germ line mutations of mismatch repair genes in hereditary nonpolyposis colorectal cancer patients with small bowel cancer: International Society for Gastrointestinal Hereditary Tumours Collaborative Study.

PURPOSE: The aim of study was to determine the clinical characteristics and mutational profiles of the mismatch repair genes in hereditary nonpolyposis colorectal cancer (HNPCC) patients with small bowel cancer (SBC). EXPERIMENTAL DESIGN: A questionnaire was mailed to 55 members of the International Society for Gastrointestinal Hereditary Tumours, requesting information regarding patients with HNPCC-associated SBC and germ line mismatch repair gene mutations. RESULTS: The study population consisted of 85 HNPCC patients with identified mismatch repair gene mutations and SBCs. SBC was the first HNPCC-associated malignancy in 14 of 41 (34.1%) patients for whom a personal history of HNPCC-associated cancers was available. The study population harbored 69 different germ line mismatch repair gene mutations, including 31 mutations in MLH1, 34 in MSH2, 3 in MSH6, and 1 in PMS2. We compared the distribution of the mismatch repair mutations in our study population with that in a control group, including all pathogenic mismatch repair mutations of the International Society for Gastrointestinal Hereditary Tumours database (excluding those in our study population). In patients with MSH2 mutations, patients with HNPCC-associated SBCs had fewer mutations in the MutL homologue interaction domain (2.9% versus 19.9%, P = 0.019) but an increased frequency of mutations in codons 626 to 733, a domain that has not previously been associated with a known function, versus the control group (26.5% versus 2.8%, P < 0.001). CONCLUSIONS: In HNPCC patients, SBC can be the first and only cancer and may develop as soon as the early teens. The distribution of MSH2 mutations found in patients with HNPCC-associated SBCs significantly differed from that found in the control group (P < 0.001).

Founder and recurrent CDH1 mutations in families with hereditary diffuse gastric cancer.

CONTEXT: Hereditary diffuse gastric cancer is caused by germline mutations in the epithelial cadherin (CDH1) gene and is characterized by an increased risk for diffuse gastric cancer and lobular breast cancer. OBJECTIVE: To determine whether recurring germline CDH1 mutations occurred due to independent mutational events or common ancestry. DESIGN, SETTING, AND PATIENTS: Thirty-eight families diagnosed clinically with hereditary diffuse gastric cancer were accrued between November 2004 and January 2006 and were analyzed for CDH1 mutations as part of an ongoing study at the British Columbia Cancer Agency. Twenty-six families had at least 2 gastric cancer cases with 1 case of diffuse gastric cancer in a person younger than 50 years; 12 families had either a single case of diffuse gastric cancer diagnosed in a person younger than 35 years or multiple cases of diffuse gastric cancer diagnosed in persons older than 50 years. MAIN OUTCOME MEASURES: Classification of family members as carriers or noncarriers of CDH1 mutations. Haplotype analysis to assess recurring mutations for common ancestry was performed on 7 families from this study and 7 previously reported families with the same mutations. RESULTS: Thirteen mutations (6 novel) were identified in 15 of the 38 families (40% detection rate). The 1137G>A splicing mutation and the 1901C>T (A634V) missense/splicing mutation occurred on common haplotypes in 2 families but on different haplotypes in a third family. The 2195G>A (R732Q) missense/splicing mutation occurred in 2 families on different haplotypes. The 2064-2065delTG mutation occurred on a common haplotype in 2 families. Two families from this study plus 2 additional families carrying the novel 2398delC mutation shared a common haplotype, suggesting a founder effect. All 4 families originate from the southeast coast of Newfoundland. Due to concentrations of lobular breast cancer cases, 2 branches of this family had been diagnosed as having hereditary breast cancer and were tested for BRCA mutations. Within these 4 families, the cumulative risk by age 75 years in mutation carriers for clinically detected gastric cancer was 40% (95% confidence interval [CI], 12%-91%) for males and 63% (95% CI, 19%-99%) for females and the risk for breast cancer in female mutation carriers was 52% (95% CI, 29%-94%). CONCLUSIONS: Recurrent CDH1 mutations in families with hereditary diffuse gastric cancer are due to both independent mutational events and common ancestry. The presence of a founder mutation from Newfoundland is strongly supported.

Multi-gene panel testing for hereditary cancer susceptibility in a rural Familial Cancer Program.

This study explores our Familial Cancer Program's experience implementing multi-gene panel testing in a largely rural patient population. We conducted a retrospective review of patients undergoing panel testing between May 2011 and August 2015. Our goal was to evaluate factors that might be predictors of identifying variants (pathogenic or uncertain significance) and to assess clinical management changes due to testing. We utilized a structured family history tool to determine the significance of patient's family histories with respect to identification of genetic variants. A total of 227 patients underwent panel testing at our center and 67 patients (29.5 %) had variants identified, with 8 (3.5 %) having multiple variants. Overall, 44 patients (19.4 %) had a variant of uncertain significance (VUS) and 28 patients (12.3 %) had a pathogenic variant detected, with 10 (4.4 %) having pathogenic variants in highly penetrant genes. We found no statistical difference in patient familial and personal cancer history, age, rural status, Ashkenazi Jewish ancestry, insurance coverage and prior single-gene testing among those with pathogenic, VUS and negative panel testing results. There were no predictors of pathogenic variants on regression analysis. Panel testing changed cancer screening and management guidelines from that expected based on family history alone in 13.2 % of patients. Ultimately, cancer panel testing does yield critical information not identified by traditional single gene testing but maximal utility through a broad range of personal and family histories requires improved interpretation of variants.