Cancer Susceptibility Mutations Research Articles

Abstract 7334: Germline mutations in cancer susceptibility genes in patients with mucosal melanoma

Abstract Background: Mucosal melanoma (MM) is the rarest subtype of melanoma with markedly worse outcomes compared to cutaneous melanoma (CM). Unlike CM which is driven by somatic mutations due to UV exposure, risk factors for MM are less defined. While germline mutations in cancer susceptibility genes are well-studied in CM, they are less understood in MM. Herein, we aimed to identify the prevalence of germline mutations in cancer susceptibility genes in a large MM cohort. Methods: A cohort of 247 MM patients (pts) from MD Anderson Cancer Center with available blood for germline sequencing was identified. Pt characteristics were reflective of U.S. MM population with median age of 63, 60% females and 84.6% white. Clinicodemographic features of pts including tumor site, key somatic mutations (BRAF, NRAS, KIT) and personal history of other malignancies were abstracted, and their frequencies were compared in pts with and w/o germline mutation. Frequency of MITF and CHEK2 alleles were compared to expected population control rate based on TOPMED by Fisher’s exact test. Results: Among 247 pts, 10.9% had germline mutations, primarily in MITF (c.G952A:p.E318K) (2.4%) and CHEK2 (c.1100delC:p.T367fs) (1.6%) at OR of 13.9 (95%CI 5.0, 30.9) and 16.4 (4.4, 42.9) compared to population control rate (Table 1). MM sites of origin were gastrointestinal (36%), genitourinary (34%) and head & neck (30%). In terms of somatic mutations, KIT (26%) was most common, followed by NRAS (15%), non-V600E BRAF (6.5%) and BRAF V600E (2.4%). These variables did not differ between those with and w/o germline mutation. Pts with germline mutation had a higher incidence of non-melanoma malignancies (48% vs 29%; p=0.044). Table 1. Summary of identified germline mutations in the mucosal melanoma cohort. Germline mutation Protein MITF (N= 6) p.E318K CHEK2 (N=4) p.T367fs MUYTH p.G368D ATM splice ATM p.L263fs ATM p.R1875X ATM p.L1327X ATM p.A2067D ATM p.R2034X BRCA2 p.A1689fs CHEK2 p.S400T ERCC3 p.R109X MITF p.C29Y NF1 p.L1183R PALB2 p.V221X POLE p.D287E TP53 p.R306X TP53 p.V73Wfs*50 TSC1 p.Q844X Conclusions: This study reports a high prevalence of germline cancer susceptibility mutations in the largest cohort of MM to date, including mutations which are actionable. There is overlap with known MITF risk alleles for CM. We are currently performing a GWAS to comprehensively understand the genetic architecture of risk in MM. Citation Format: Afsaneh Amouzegar, Xiaogang Wu, James Long, Sabitha Prabhakaran, Latasha Little, Curtis Gumbs, Jared Malke, Julie Simon, Jianhua Zhang, Jennifer Wargo, Paul Scheet, Justin W. Wong, Priyadharsini Nagarajan, Jennifer L. McQuade, Andrew Futreal. Germline mutations in cancer susceptibility genes in patients with mucosal melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7334.

Pharmaceutical Agents as Potential Drivers in the Development of Early-Onset Colorectal Cancer: Case-Control Study.

The incidence of early-onset colorectal cancer (EOCRC) rose abruptly in the mid 1990s, is continuing to increase, and has now been noted in many countries. By 2030, 25% of American patients diagnosed with rectal cancer will be 49 years or younger. The large majority of EOCRC cases are not found in patients with germline cancer susceptibility mutations (eg, Lynch syndrome) or inflammatory bowel disease. Thus, environmental or lifestyle factors are suspected drivers. Obesity, sedentary lifestyle, diabetes mellitus, smoking, alcohol, or antibiotics affecting the gut microbiome have been proposed. However, these factors, which have been present since the 1950s, have not yet been conclusively linked to the abrupt increase in EOCRC. The sharp increase suggests the introduction of a new risk factor for young people. We hypothesized that the driver may be an off-target effect of a pharmaceutical agent (ie, one requiring regulatory approval before its use in the general population or an off-label use of a previously approved agent) in a genetically susceptible subgroup of young adults. If a pharmaceutical agent is an EOCRC driving factor, regulatory risk mitigation strategies could be used. We aimed to evaluate the possibility that pharmaceutical agents serve as risk factors for EOCRC. We conducted a case-control study. Data including demographics, comorbidities, and complete medication dispensing history were obtained from the electronic medical records database of Maccabi Healthcare Services, a state-mandated health provider covering 26% of the Israeli population. The participants included 941 patients with EOCRC (≤50 years of age) diagnosed during 2001-2019 who were density matched at a ratio of 1:10 with 9410 control patients. Patients with inflammatory bowel disease and those with a known inherited cancer susceptibility syndrome were excluded. An advanced machine learning algorithm based on gradient boosted decision trees coupled with Bayesian model optimization and repeated data sampling was used to sort through the very high-dimensional drug dispensing data to identify specific medication groups that were consistently linked with EOCRC while allowing for synergistic or antagonistic interactions between medications. Odds ratios for the identified medication classes were obtained from a conditional logistic regression model. Out of more than 800 medication classes, we identified several classes that were consistently associated with EOCRC risk across independently trained models. Interactions between medication groups did not seem to substantially affect the risk. In our analysis, drug groups that were consistently positively associated with EOCRC included beta blockers and valerian (Valeriana officinalis). Antibiotics were not consistently associated with EOCRC risk. Our analysis suggests that the development of EOCRC may be correlated with prior use of specific medications. Additional analyses should be used to validate the results. The mechanism of action inducing EOCRC by candidate pharmaceutical agents will then need to be determined.

Polygenic Risk and Chemotherapy-Related Subsequent Malignancies in Childhood Cancer Survivors: A Childhood Cancer Survivor Study and St Jude Lifetime Cohort Study Report.

Chemotherapeutic exposures are associated with subsequent malignant neoplasm (SMN) risk. The role of genetic susceptibility in chemotherapy-related SMNs should be defined as use of radiation therapy (RT) decreases. SMNs among long-term childhood cancer survivors of European (EUR; N = 9,895) and African (AFR; N = 718) genetic ancestry from the Childhood Cancer Survivor Study and St Jude Lifetime Cohort Study were evaluated. An externally validated 179-variant polygenic risk score (PRS) associated with pleiotropic adult cancer risk from the UK Biobank Study (N > 400,000) was computed for each survivor. SMN cumulative incidence comparing top and bottom PRS quintiles was estimated, along with hazard ratios (HRs) from proportional hazards models. A total of 1,594 survivors developed SMNs, with basal cell carcinomas (n = 822), breast cancers (n = 235), and thyroid cancers (n = 221) being the most frequent. Although SMN risk associations with the PRS were extremely modest in RT-exposed EUR survivors (HR, 1.22; P = .048; n = 4,630), the increase in 30-year SMN cumulative incidence and HRs comparing top and bottom PRS quintiles was statistically significant among nonirradiated EUR survivors (n = 4,322) treated with alkylating agents (17% v 6%; HR, 2.46; P < .01), anthracyclines (20% v 8%; HR, 2.86; P < .001), epipodophyllotoxins (23% v 1%; HR, 12.20; P < .001), or platinums (46% v 7%; HR, 8.58; P < .01). This PRS also significantly modified epipodophyllotoxin-related SMN risk among nonirradiated AFR survivors (n = 414; P < .01). Improvements in prediction attributable to the PRS were greatest for epipodophyllotoxin-exposed (AUC, 0.71 v 0.63) and platinum-exposed (AUC,0.68 v 0.58) survivors. A pleiotropic cancer PRS has strong potential for improving SMN clinical risk stratification among nonirradiated survivors treated with specific chemotherapies. A polygenic risk screening approach may be a valuable complement to an early screening strategy on the basis of treatments and rare cancer-susceptibility mutations.

Identification of a Novel FAM135B Cancer Susceptibility Mutation in a Family with Multiple Cases of MLL-Rearranged AML

Background: Familial aggregation of malignancies, including leukemia, is rarely reported due to the scattered cases, weakened bonding among generations, and low birth rates in modern society. The emerging demands for predicting and preventing cancer development are outgrowing the progress in the studies of the mechanism underlying the propensity of malignancies. Results: Here we reported a family with 4 cases of acute leukemia (AL) and four solid tumors (2 for lung cancer, 1 for renal clear cell carcinoma, and one for rectal adenocarcinoma). Besides, one member in the family was diagnosed with intraspinal cavernous hemangioma, and another one was diagnosed with congenital heart disease (transposition of the great arteries). 2 out of 4 AL patients were cousins and diagnosed with acute monocytic leukemia (AML-M5 with MLL-rearrangement) in our center. Whole genome sequencing was performed on two patients with AML, two patients with solid tumors, one obligated carrier, and three healthy members. Using an in-house bioinformatic data analysis pipeline, we identified 18 single nucleotide variants (SNVs) and four insertions/deletions (Indel) in all the affected members and one obligated carrier while absent in healthy members. Genotyping of these variants in 57 family members confirmed that 18/22 variants co-segregated with the malignant phenotype of this family. By screening for these 18 variants in 13 AL pedigrees, we narrow our cancer-predisposing candidate list to one variant, hitting FAM135B (family with sequence similarity 135 member B; NM_015912: exon13:c.A2621G:p.E874G), which is recurrent in another AML pedigree with two cases in two consecutive generations. This mutation resides in a highly conserved locus among species and is predicted to be deleterious. FAM135B is predicted to encode serine esterase, and the role of FAM135B in AML was not documented. Intriguingly, all the affected familial AML cases from two pedigrees were diagnosed with AML-M5 with MLL-rearrangement. Moreover, this mutation is recurrent in sporadic adult AML cohort (6/467), among which half (3/6) were AML-M5, two M3, and one M2. Functionally, we found that overexpression of FAM135B promotes the proliferation and colony formation of AML cells. Consistently, downregulation of FAM135B nearly abolished the colony-forming capacity of AML cells and impaired cell proliferation. Further studies on the role of FAM135B in AML development are under investigation. Conclusion: We identify a novel cancer-predisposing gene, FAM135B, and its mutation E874G occurred in both familial and sporadic AML cases, especially AML-M5 with MLL-rearrangement.

Landscape of germline cancer predisposition mutations testing and management in pediatrics: Implications for research and clinical care.

As germline genetic testing capacities have improved over the last two decades, increasingly more people are newly diagnosed with germline cancer susceptibility mutations. In the wake of this growth, there remain limitations in both testing strategies and translation of these results into morbidity- and mortality-reducing practices, with pediatric populations remaining especially vulnerable. To face the challenges evoked by an expanding diversity of germline cancer mutations, we can draw upon a model cancer-associated genetic condition for which we have developed a breadth of expertise in managing, Trisomy 21. We can additionally apply advances in other disciplines, such as oncofertility and pharmacogenomics, to enhance care delivery. Herein, we describe the history of germline mutation testing, epidemiology of known germline cancer mutations and their associations with childhood cancer, testing limitations, and future directions for research and clinical care.

Clinical significance of next-generation sequencing in Chinese patients with relapsed/refractory Wilm’s tumor.

e22003 Background: Medical advances have been greatly improved in the survival rate for Wilms’ tumor, but the survival is still dismal for relapsed/refractory (R/R) patients. In the present study, we aimed to investigated the genomic profiling and the incidence of germline cancer susceptibility mutations of Chinese patients with R/R WT. Methods: From Jun 18, 2020 to Dec 22, 2020, the tumor specimens with matched blood samples obtained from R/R pediatric WT in Sun Yat-Sen University Cancer Center were performed next-generation sequencing (NGS) using a 539 cancer-related gene panel in a CAP-certified laboratory (Simcere Diagnostic Co, Ltd). Clinical information including age, gender and tumor histology were collected. Somatic and germline variations including single nucleotide variants (SNV), insertion-deletion variants (Indels), copy number variations (CNVs) and fusion, as well as tumor mutational burden (TMB)/microsatellite instability (MSI) were analyzed. IHC staining for PD-L1 expression was performed by FDA-approved VENTANA PD-L1(SP263) assay. Results: Eight patients with R/R WT were enrolled in this study, including 5 males and 3 females, with a median age of 6 years old (range, 3-14). All of the pathology was identified as favorable histology WT (FHWT). Of the specimens, 8 were from pulmonary and 1from peritoneum. We identified 152 reportable molecular aberrations, with a median of 19 (0-24). CNVs accounted for the majority of the total somatic aberrations, followed by SNVs, the percentage was 77% and 22%, respectively. Genes with either CNVs or SNVs were detected in FGFR1 (n=4), ERBB2(n=3), MYCN(n=4), MET(n=2), CDK4/6(n=2), TP53(n=2), CTNNB1(n=2), MYC(n=2), NF1(n=2), MDM4(n=2), CHEK2(n=1), FBXW7(n=1), EGFR(n=1). Notable cancer driver mutations were also characterized, such as the amplifications of ERBB2/MET/EGFR/FGFR1, and the point variations of CHEK2/FBXW7/NF1. Besides, a novel ASB12 intergenic region- AMER1 fusion was identified. Both of the patients available for PD-L1 evaluation showed negative PD-L1 expression on tumor cells. The median TMB was 1.47 (range, 0-7.8). All patients were microsatellite stabilization (MSS). A 4-year-old patient suffering peritoneal relapse harbored a germline pathogenic mutation in FANCA (c.1777-1G&gt;C, intron 19), this locus has never been reported in WT before. Conclusions: We discovered some driver genes mutations which potentially sensitive to the corresponding targeted drugs in Chinese R/R WT patients. Large sample size was needed to provide a better understanding of molecular features in R/R WT patients to achieve precision medicine.

Prospective genomic testing of unselected cancer patients yields insights about cancer susceptibility and noncancer disease with therapeutic implications.

10603 Background: Clinicians have used strict criteria to determine eligibility for cancer susceptibility (CS) testing and have limited genetic assessment to cancer-related genes. However, half of all CS mutation carriers are missed by criteria-based testing and there may be an unrecognized opportunity to modify care for patients who have rare but actionable genetic disorders as defined by the American College of Medical Genetics (ACMG). With the aim of improving patient outcomes through precision genomics, we initiated an enterprise-wide program to offer somatic and germline sequencing to all patients. Methods: We offer consented patients clinical grade paired somatic &amp; germline WES/ RNA seq and panel germline testing for cancer (156 genes) and ACMG disorders (59 genes). Results are reviewed by a Precision Oncology Tumor Board. Somatic results are returned by the treating team. Germline results are returned by phone (genetic counselor, GC) followed by a clinic visit (GC+MD) for those with pathogenic/likely pathogenic (P/LP) mutations and selected variants of uncertain significant. We evaluated the proportions of patients with somatic findings suggestive of germline conditions and those carrying P/LP mutations in CS and ACMG genes. Results: 1,804 patients enrolled and received somatic sequencing: 52% female; 51% non-Hispanic White/ 20% Hispanic White/ 18% Asian/ 4% Black/ 7% other; median age 64. Review of somatic data suggest that 14% have findings suggestive of germline conditions based on factors such as TMB, MSI, and young age. Of the patients offered germline testing, &gt;95% opted to receive CS/ACMG results. To date, we have sequenced 684 patients for CS and 647 for ACMG. 18% of patients had P/LP mutations in CS genes and 4% had P/LP mutations in ACMG non-cancer genes (Table). Conclusions: Prospective somatic/germline sequencing of unselected cancer patients reveals tumor findings suggestive of germline disorders and identifies patients with CS and non-cancer genetic conditions. These findings highlight the promise of a comprehensive sequencing approach to help guide cancer treatment, management of unrecognized cancer risk and the need for concomitant management of rare disorders such as arrhythmogenic cardiomyopathy and susceptibility to adverse reactions with anesthesia.[Table: see text]

Design of a study to implement population-based risk assessment for hereditary cancer genetic testing in primary care

Identifying patients with high genetic risk for cancer has important clinical ramifications, but hereditary cancer risk is often not identified because of testing barriers at both the provider and patient level. It is unknown how to best implement appropriate genetic testing and follow-up care into an operating primary care clinic. Implementation studies to date have been conducted in high resourced facilities under optimal conditions, often not at the clinic level. This study aims to compare and evaluate two population-wide engagement strategies for identifying members of a primary care clinic's population with a family or personal history of cancer and offering high-risk individuals genetic testing for cancer susceptibility mutations. The two engagement strategies are: 1) point of care screening (POC), conducted when a patient is scheduled for an appointment and 2) direct patient engagement (DPE), where outreach provides the patient an opportunity to complete screening online on their own time. The study will identify changes, problems, and inefficiencies in clinical flow during and after the implementation of risk assessment and genomic testing for cancer risk across primary care clinics. It will also evaluate the effects of the two engagement strategies on patient, provider, and clinic leader outcomes, including perceptions of benefits, harms, and satisfaction with the engagement strategy and process of cancer risk assessment and genetic testing, across gender, racial/ethnic, socioeconomic, and genetic literacy divides. Finally, the study will evaluate the cost-effectiveness and budget impact of each engagement strategy.

Patterns of care for risk reducing surgery in non-BRCA and Lynch ovarian cancer susceptibility mutation carriers

Objective: Current guidelines recommend risk-reducing bilateral salpingo-oophorectomy (RRSO) for women with known non-BRCA and Lynch ovarian cancer susceptibility gene mutations. Optimal timing for RRSO remains unclear. We sought to characterize the practice patterns for these women at our 2 institutions.

780P Cancer susceptibility mutations in Chinese patients with urothelial malignancies

780P Cancer susceptibility mutations in Chinese patients with urothelial malignancies

Management of high, moderate, and low penetrance ovarian cancer susceptibility mutations: an assessment of current risk reduction practices

ObjectiveLimited information exists regarding risk reduction strategies for women with moderate and low penetrance ovarian cancer susceptibility mutations. We sought to assess current risk reduction practice patterns for carriers of...

Abstract B109: Architecture of increased breast cancer risk

Abstract Purpose: To highlight the importance of building a high-risk breast cancer clinic for women who do not have a BRCA 1, BRCA 2 or other highly penetrant cancer susceptibility mutation. Background: Breast cancer is the most common cancer in women and the second most prevalent cause of cancer death of women in the United States; the lifetime risk for breast cancer in women is approximately 12%. Women may be at increased risk for breast cancer for many reasons including family history, genetic alterations, age, reproductive status and menstrual history. Most women who are at increased risk of developing breast cancer do not have a BRCA 1, BRCA 2 or other mutation. The majority of breast cancer diagnoses are due to acquired somatic mutations; only 5 to 10% of breast cancer diagnoses are attributable to highly penetrant Mendelian cancer susceptibility genes. White women with Ashkenazi Jewish ancestry tend to have a higher incidence of BRCA 1 and 2 mutations; traditionally, most research efforts about highly penetrant genes have been focused on this group rather than other racial and ethnic groups. However, there is a great need to study breast cancer risk-reduction strategies in racial and ethnic minorities in the United States, particularly because most breast cancers are not caused by BRCA 1 and 2 mutations. City of Hope is located approximately 21 miles northeast of Los Angeles and operates 13 clinical practice locations including Los Angeles, Orange, Riverside, San Bernardino and Ventura counties. These five counties are home to the majority of California's multicultural and ethnic residents where San Bernardino County has the highest percentage of Hispanics (49.9%) and blacks (8.3%), Ventura County has the highest percentage of whites (48.1%), and Orange County has the highest concentration of Asians (18.2%). It has been established in the literature that the greatest benefit from breast cancer prevention strategies comes from treating women who are at high risk of the disease. While it is important to build a high-risk breast cancer clinic for women with genetic mutations, it is equally important to build a high-risk breast clinic for women who are at increased risk of breast cancer but do not have a mutation, particularly because most breast cancer is diagnosed in this population. In addition, it is crucial to educate high-risk patients that although they may have tested negative for a genetic mutation if they have a family history of breast cancer, they warrant close clinical surveillance. Methods: We are proposing a retrospective, descriptive study of data that will be collected as part of a high-risk breast cancer program implemented by City of Hope. Results/Conclusions: We expect to discuss the findings related to serving women of all races and ethnicities who do not have a mutation in a highly penetrant gene mutation. Citation Format: Karen Herold, Lisa D. Yee, Chidimma M. Kalu, Laura L. Kruper, Veronica C. Jones, Amy C. Polverini, Sharon Clancy, Tanya A. Chavez, Jackelyn A. Alva-Ornelas, Noe R Chavez, Ellen J. Rippberger, Jerneja Tomsic, Christopher Sistrunk, Ombeni Idassi, Daniel B. Schmolze, Courtney Vito, Alan Nunez, Angela K. Wong, Krista M. Round, Christine Thai, Angelica Sanchez, Margarita Robles, Kendall Kennedy, Terry Hyslop, Victoria L. Seewaldt. Architecture of increased breast cancer risk [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr B109.

Cascading After Peridiagnostic Cancer Genetic Testing: An Alternative to Population-Based Screening.

PURPOSEDespite advances in DNA sequencing technology and expanded medical guidelines, the vast majority of individuals carrying pathogenic variants of common cancer susceptibility genes have yet to be identified. An alternative to population-wide genetic screening of healthy individuals would exploit the trend for genetic testing at the time of cancer diagnosis to guide therapy and prevention, combined with augmented familial diffusion or “cascade” of genomic risk information.METHODSUsing a multiple linear regression model, we derived the time interval to detect an estimated 3.9 million individuals in the United States with a pathogenic variant in 1 of 18 cancer susceptibility genes. We analyzed the impact of the proportion of incident patients sequenced, varying observed frequencies of pathogenic germline variants in patients with cancer, differential rates of diffusion of genetic information in families, and family size.RESULTSThe time to detect inherited cancer predisposing variants in the population is affected by the extent of cascade to first-, second-, and third-degree relatives (FDR, SDR, TDR, respectively), family size, prevalence of mutations in patients with cancer, and the proportion of patients with cancer sequenced. In a representative scenario, assuming a 7% prevalence of pathogenic variants across cancer types, an average family size of 3 per generation, and 15% of incident patients with cancer in the United States undergoing germline testing, the time to detect all 3.9 million individuals with pathogenic variants in 18 cancer susceptibility genes would be 46.2, 22.3, 13.6, and 9.9 years if 10%, 25%, 50%, and 70%, respectively, of all FDR, SDR, and TDR were tested for familial mutations.CONCLUSIONPeridiagnostic and cascade cancer genetic testing offers an alternative strategy to achieve population-wide identification of cancer susceptibility mutations.

Identification and Confirmation of Potentially Actionable Germline Mutations in Tumor-Only Genomic Sequencing.

Tumor-only genomic profiling (TGP) is increasingly advocated for all patients with cancer given the possible therapeutic implications. It is critical to develop clinical algorithms to identify and address potentially actionable germline findings identified by TGP. A multidisciplinary team analyzed publicly available data for genes in which mutations are implicated in germline cancer susceptibility and established a pipeline to automate clinical referral for evaluation of TGP findings. A total of 2,308 patients underwent TGP, with 81 patients (3.5%) identified by the automatic referral pipeline; 37 patients (1.6%) were referred outside the pipeline based on concerns by the molecular geneticist, pathologist, or oncologist regarding genotype-phenotype correlation. Thirty-one patients (38%) and 17 patients (46%) underwent germline testing from the automatic pipeline and other referrals, respectively, and of these patients, 23 (72%) and four (24%) had confirmed germline pathogenic variants (GPVs), respectively. The majority of confirmed GPVs were in automatic referral genes, with BRCA2 being most common (confirmed GPVs in 11 [85%] of 13 patients tested), followed by PALB2 (five [67%] of six patients), BRCA1 (two [40%] of five patients), MSH6 (two of three patients), and MLH1 (two of two patients). Forty-eight percent of confirmed GPVs were found in tumors known to be associated with germline mutations in the gene. Germline testing was not performed in 50 (62%) of 81 patients identified by automatic referral as a result of poor patient health or death (30%), lack of follow-up (30%), and patient refusal (30%). Of patients undergoing TGP, 5% had somatic findings triggering referral, and implementation of an automatic referral pipeline based solely on gene versus other clinical or molecular features resulted in a 74% germline confirmation. However, only 41% of referred patients underwent germline testing. Systems-based approaches are needed to identify carriers of actionable germline cancer susceptibility mutations identified by TGP.

Management of high, moderate, and low penetrance ovarian cancer susceptibility gene mutations: An assessment of current practice patterns.

1536 Background: Limited information exists regarding appropriate risk-reduction strategies for women with moderate and low penetrance ovarian cancer (OVCA) susceptibility mutations. We sought to assess current practice patterns for women with these genetic changes through a survey of members of the Society of Gynecologic Oncology (SGO). Methods: All full SGO members were e-mailed a survey consisting of two vignettes: 1) a 35-year-old premenopausal woman who desires pregnancy; 2) a 55-year-old postmenopausal woman with multiple comorbidities. Each vignette contained sub-scenarios in which the patient had either a BRCA1 (RR = 30-60), RAD51C (RR = 5.0) or ATM (RR 1.5-2.0) OVCA susceptibility mutation. Respondents were queried about their preferred management approach. Chi-square test was used for statistical analysis. Results: 193 (15%) of 1284 SGO members responded. 58% were in academic practice. For the premenopausal woman, 52%, 13% and 6% would perform an RRSO prior to age 40 in the setting of a BRCA1, RAD51C and ATM mutation respectively. 47%, 68% and 9% would perform RRSO at 40-50; and 0%, 9% and 23% would perform RRSO at menopause, depending on the gene mutated. For the postmenopausal woman with comorbidities, 98%, 85% and 42% would proceed with RRSO in the setting of a BRCA1, RAD51C and ATM mutation respectively; 2%, 8% and 39% would observe (with/without screening); and 0%, 7% and 19% would do further research prior to proceeding. Distribution of responses for carriers of RAD51C and ATM mutations were different from BRCA1 in both vignettes [p &lt; 0.001]. Conclusions: Respondents were more likely to perform RRSO earlier and more frequently in the setting of a BRCA1 mutation compared to either a RAD51C or ATM mutation. However, there was lack of consensus in management of the moderate and low penetrance OVCA susceptibility mutations. These patterns likely reflect the limited information available regarding the timing and magnitude of risk associated with these genes. Given the immediate and long-term morbidity of oophorectomy, more data regarding age-specific risks and appropriate risk-reduction strategies for moderate and low penetrance OVCA susceptibility mutations is needed.

Comparison of risk-reducing surgery in women with BRCA and non-BRCA ovarian cancer susceptibility genes.

1547 Background: Risk reducing gynecologic surgery (RRSO) is standard of care for women with BRCA mutations. The optimal management for women with non-BRCA ovarian cancer susceptibility mutations remains unclear. We sought to characterize the practice patterns for these women at our two institutions. Methods: Women with germline ovarian cancer susceptibility genes who had a RRSO were identified from 1/2000-1/2019 in an IRB approved study. All patients were asymptomatic with no suspicion for malignancy at time of RRSO. Clinico-pathologic characteristics were extracted from the medical records. Continuous variables were analyzed with Kruskal-Wallis and categorical variables analyzed with chi square and t-tests. Results: 152 BRCA1, 95 BRCA2, and 63 Non-BRCA mutation carriers were identified—50 Lynch (22 MLH1, 13 MSH2, 13 MSH6, 2 PMS2) and 13 Other (6 BRIP1, 2 RAD51C, 5 RAD51D). There was no difference between age at testing, age at RRSO, and interval between testing and RRSO between groups. Genetic counseling was higher in Non-BRCA patients. Family history of ovarian cancer was more common in women with BRCA1 and Other germline mutations compared to BRCA2 and Lynch. Family and personal history of breast cancer was high in all groups except Lynch carriers. Prophylactic mastectomy was seen mostly in BRCA mutation carriers. Concomitant hysterectomy was performed in the majority of women (BRCA1 59%, BRCA2 57%, and Other 62%), with the highest frequency in Lynch carriers (86%, p&lt;.01). Occult cancer was only seen in BRCA mutation carriers: BRCA1 (7%), BRCA2 (2%), Lynch (0%), Other (0%). Conclusions: In this cohort, women with Non-BRCA mutations are managed similarly to women with BRCA mutations. We observed no occult cancers in Non-BRCA patients. The optimal role of surgery as a risk reducing strategy in this group requires further study. [Table: see text]

Synergistic Interaction of HOXB13 and CIP2A Predisposes to Aggressive Prostate Cancer.

Distinguishing aggressive prostate cancer from indolent disease improves personalized treatment. Although only few genetic variants are known to predispose to aggressive prostate cancer, synergistic interactions of HOXB13 G84E high-risk prostate cancer susceptibility mutation with other genetic loci remain unknown. The purpose of this study was to examine the interplay of HOXB13 rs138213197 (G84E) and CIP2A rs2278911 (R229Q) germline variants on prostate cancer risk. Genotyping was done in Finnish discovery cohort (n = 2,738) and validated in Swedish (n = 3,132) and independent Finnish (n = 1,155) prostate cancer cohorts. Expression pattern analysis was followed by functional studies in prostate cancer cell models. Interplay of HOXB13 (G84E) and CIP2A (R229Q) variants results in highest observed inherited prostate cancer risk (OR, 21.1; P = 0.000024). In addition, this synergism indicates a significant association of HOXB13 T and CIP2A T dual carriers with elevated risk for high Gleason score (OR, 2.3; P = 0.025) and worse prostate cancer-specific life expectancy (HR, 3.9; P = 0.048), and it is linked with high PSA at diagnosis (OR, 3.30; P = 0.028). Furthermore, combined high expression of HOXB13-CIP2A correlates with earlier biochemical recurrence. Finally, functional experiments showed that ectopic expression of variants stimulates prostate cancer cell growth and migration. In addition, we observed strong chromatin binding of HOXB13 at CIP2A locus and revealed that HOXB13 functionally promotes CIP2A transcription. The study is limited to retrospective Nordic cohorts. Simultaneous presence of HOXB13 T and CIP2A T alleles confers for high prostate cancer risk and aggressiveness of disease, earlier biochemical relapse, and lower disease-specific life expectancy. HOXB13 protein binds to CIP2A gene and functionally promotes CIP2A transcription.

Genomic profiling of synchronous triple primary tumors of the lung, thyroid and kidney in a young female patient: A case report.

Synchronous multiple primary malignant tumors (MPMTs) are rare in young adults. Genomic profiling of synchronous MPMTs has not been systematically investigated to elucidate their genetic associations, but may be important to assist diagnosis and guide appropriate treatment strategy. In the present study, mutation profiling was performed using targeted next generation sequencing (NGS) on 416 cancer-related genes in synchronous triple primary tumors of the lung, kidney and thyroid in a 32-year-old female patient. The patient was diagnosed with moderately differentiated lung adenocarcinoma (T2aN0M0; stage IB), renal clear cell carcinoma (T1aN0M0; stage I), and thyroid papillary carcinoma (T1N1aM0, stage III) by pathological assessments. Clinically actionable mutations in EGFR and BRAF genes were identified in the lung and the thyroid lesions, respectively. Three tumors demonstrated distinct genomic profiles, suggesting that all tumors were independent primary tumors, which was consistent with histopathological assessment. Three potential germline cancer susceptibility mutations were shared between this patient and her father who was diagnosed with lung cancer. The present results demonstrated that, in the context of identical germline background and environmental exposure, multiple synchronous tumors in the same patient may have distinct mutation profiles and can be driven by distinct molecular events. Combination therapies may need to be considered during treatment decision-making.

Frequency of Germline Mutations in Cancer Susceptibility Genes in Malignant Mesothelioma.

The aim of the current study was to determine the prevalence and clinical predictors of germline cancer susceptibility mutations in patients with malignant mesothelioma (MM). We performed targeted capture and next-generation sequencing of 85 cancer susceptibility genes on germline DNA from 198 patients with pleural, peritoneal, and tunica vaginalis MM. Twenty-four germline mutations were identified in 13 genes in 23 (12%) of 198 patients. BAP1 mutations were the most common (n = 6; 25%). The remaining were in genes involved in DNA damage sensing and repair (n = 14), oxygen sensing (n = 2), endosome trafficking (n = 1), and cell growth (n = 1). Pleural site (odds ratio [OR], 0.23; 95% CI, 0.10 to 0.58; P < .01), asbestos exposure (OR, 0.28; 95% CI, 0.11 to 0.72; P < .01), and older age (OR, 0.95; 95% CI, 0.92 to 0.99; P = .01) were associated with decreased odds of carrying a germline mutation, whereas having a second cancer diagnosis (OR, 3.33; 95% CI, 1.22 to 9.07; P = .02) significantly increased the odds. The odds of carrying a mutation in BAP1 (OR, 1,658; 95% CI, 199 to 76,224; P < .001), BRCA2 (OR, 5; 95% CI, 1.0 to 14.7; P = .03), CDKN2A (OR, 53; 95% CI, 6 to 249; P < .001), TMEM127 (OR, 88; 95% CI, 1.7 to 1,105; P = .01), VHL (OR, 51; 95% CI, 1.1 to 453; P = .02), and WT1 (OR, 20; 95% CI, 0.5 to 135; P = .049) were significantly higher in MM cases than in a noncancer control population. Tumor sequencing identified mutations in a homologous recombination pathway gene in 52% (n = 29 of 54). A significant proportion of patients with MM carry germline mutations in cancer susceptibility genes, especially those with peritoneal MM, minimal asbestos exposure, young age, and a second cancer diagnosis. These data support clinical germline genetic testing for patients with MM and provide a rationale for additional investigation of the homologous recombination pathway in MM.

Increased detection of germline cancer susceptibility mutations subsequent to tumor profiling.

e13613Background: In addition to guiding targeted therapy, tumor profiling may incidentally reveal germline mutations leading to the diagnosis of hereditary cancer predisposition. When somatic and ...