Couch, Fergus J.

AbstractGermline genetic testing for inherited cancer risk is increasingly being performed with multigene panel testing with MUTYH often included on colorectal cancer‐ and polyposis‐focused panels, as well as on broader pan‐cancer panels. With up to 1%–2% of the general population being monoallelic MUTYH carriers, pathogenic/likely pathogenic (P/LP) variants in MUTYH are one of the most common findings on multigene cancer panels. However, little is known about patient experience and understanding of monoallelic MUTYH P/LP variants, nor whether such findings influence medical management recommendations and familial communication, which this study aims to better understand. Monoallelic P/LP MUTYH carriers were recruited from the Prospective Registry of Multiplex Testing (PROMPT) and completed a cross‐sectional self‐report survey on sociodemographic characteristics, medical and family history, experiences with MUTYH genetic testing, genetics and MUTYH knowledge, perceived cancer risk, and familial communication. Of 115 eligible PROMPT participants, 49 (43%) completed the survey who were primarily female (94%), white (96%), had a history of cancer (61%), and a median age of 51.4 years. Most participants (61%) reported satisfaction with how their healthcare provider managed their genetic test result and care, and 65% of survey participants reported their provider recommended colonoscopy based on their genetic test results. Participants' responses also reflected variable levels of knowledge regarding cancer risks and screening recommendations for MUTYH carriers. The majority (98%) of participants shared their genetic test results with at least some of their relatives; however, only 13% of eligible relatives reportedly underwent cascade testing. Taken together, this study provides needed insight into the overall experiences of monoallelic MUTYH carriers and highlights numerous areas for improvement in clinician education, communication, and management of these individuals.

Abstract The aim of this cross‐sectional study was to examine whether a history of selective estrogen receptor modifiers (SERMs), tamoxifen and raloxifene, use was associated with cognitive performance, odds of mild cognitive impairment (MCI), or magnetic resonance imaging (MRI) markers of neurodegeneration associated with Alzheimer's disease. We included women with prior history of breast cancer or no prior history of any cancer at enrollment in the Mayo Clinic Study of Aging (MCSA). This information was abstracted using the Rochester Epidemiology Project medical‐linkage system. Logistic regression was used to examine associations of SERMs with odds of MCI. Linear regression models were used to examine associations of SERMs with cognitive z‐scores (Memory, Executive Function, Language, Visuospatial Skills, Global Cognition), and MRI markers. Among 2840 women aged 50 and older in the MCSA, 151 had a history of breast cancer, and 42 (28%) of these had a history of tamoxifen treatment. A total of 2235 women had no prior history of any cancer, and 76 (3%) of these had a history of raloxifene use. No significant associations between tamoxifen use and cognition, or odds of MCI were observed among women with a history of breast cancer after adjusting for confounders. Similarly, raloxifene use was not significantly associated with cognition, or odds of MCI in women without a history of cancer after adjusting for confounders. We did not find significant associations between the use of either SERM and MRI markers. Use of tamoxifen or raloxifene was not significantly associated with cognition in postmenopausal women.

Abstract Physical activity (PA) is associated with improvement in breast cancer treatment-related symptoms and survival, yet most breast cancer survivors do not meet national PA guidelines. This study aimed to identify characteristics of participants that were associated with an increased likelihood of meeting PA guidelines. Adults with breast cancer seen at Mayo Clinic (Rochester, MN) were surveyed regarding their PA participation, and those who self-reported at least 150 minutes of moderate and/or strenuous aerobic PA weekly on average were considered to be “meeting guidelines”. Three thousand participants returned PA data. Younger age, completion of the survey 7-12 years after diagnosis, absence of recurrence, no bilateral mastectomy, absence of metastatic disease, and lower BMI at the time of survey completion were associated with PA participation (P < .05 in univariate and multivariate analyses). Findings were similar when a threshold of 90 minutes was applied. These results may inform the development of targeted PA-facilitating interventions.

Abstract Women who have had breast cancer in the past are at increased risk of developing a second primary cancer (SPC), including second primary breast cancer (SPBC) or a second primary non-breast cancer (SPNBC). In the Multiethnic Cohort (MEC) Study, we conducted a prospective cohort analysis in 3,223 female breast cancer survivors from five racial/ethnic populations (White, African American, Japanese American, Latino, and Native Hawaiian) to assess the association of rare pathogenic variants (PV) in 37 known cancer predisposition genes with risk of SPC. A total of 719 (22.3%) women developed SPC, of which, 323 (10.0%) were SPBC. Germline PVs in BRCA1 (HR, 2.28; 95% CI, 1.11–4.65) and ERCC2 (HR, 3.51; 95% CI, 1.29–9.54) were significantly enriched in women with SPC. In the subtype analysis for SPBC, a significant association of ERCC2 PVs (HR, 5.09; 95% CI, 1.58–16.4) and a suggestive association of BRCA2 PVs (HR, 2.24; 95% CI, 0.91–5.55) were observed. There was also a higher risk of SPNBC in carriers of BRCA1 PVs (HR, 2.98; 95% CI, 1.21–7.36). These results provide evidence that germline PVs in BRCA1, BRCA2, and ERCC2 contribute to the development of SPC in breast cancer survivors. These findings also suggest that compromised DNA repair mechanisms could be a predisposition factor for SPC in patients with breast cancer, supporting the need for closer monitoring of SPC in women carrying PVs in these genes. Significance: This multiethnic study links germline pathogenic variants in BRCA1, BRCA2, and ERCC2 to the development of second primary cancer in breast cancer survivors, providing biological insights and biomarkers to guide patient monitoring.

Abstract Purpose: The identification of variants of uncertain significance (VUS) in the BRCA1 and BRCA2 genes by hereditary cancer testing poses great challenges for the clinical management of variant carriers. The ACMG/AMP (American College of Medical Genetics and Genomics/Association for Molecular Pathology) variant classification framework, which incorporates multiple sources of evidence, has the potential to establish the clinical relevance of many VUS. We sought to classify the clinical relevance of 133 single-nucleotide substitution variants encoding missense variants in the DNA-binding domain (DBD) of BRCA2 by incorporating results from a validated functional assay into an ACMG/AMP-variant classification model from a hereditary cancer–testing laboratory. Experimental Design: The 133 selected VUS were evaluated using a validated homology-directed double-strand DNA break repair (HDR) functional assay. Results were combined with clinical and genetic data from variant carriers in a rules-based variant classification model for BRCA2. Results: Of 133 missense variants, 44 were designated as non-functional and 89 were designated as functional in the HDR assay. When combined with genetic and clinical information from a single diagnostic laboratory in an ACMG/AMP-variant classification framework, 66 variants previously classified by the diagnostic laboratory were correctly classified, and 62 of 67 VUS (92.5%) were reclassified as likely pathogenic (n = 22) or likely benign (n = 40). In total, 44 variants were classified as pathogenic/likely pathogenic, 84 as benign/likely benign, and 5 remained as VUS. Conclusions: Incorporation of HDR functional analysis into an ACMG/AMP framework model substantially improves BRCA2 VUS re-classification and provides an important tool for determining the clinical relevance of individual BRCA2 VUS.

Abstract Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with low overall survival rates and high molecular heterogeneity; therefore, few targeted therapies are available. The luminal androgen receptor (LAR) is the most consistently identified TNBC subtype, but the clinical utility has yet to be established. Here, we constructed a novel genomic classifier, LAR-Sig, that distinguishes the LAR subtype from other TNBC subtypes and provide evidence that it is a clinically distinct disease. A meta-analysis of seven TNBC datasets (n = 1086 samples) from neoadjuvant clinical trials demonstrated that LAR patients have significantly reduced response (pCR) rates than non-LAR TNBC patients (odds ratio = 2.11, 95% CI: 1.33, 2.89). Moreover, deconvolution of the tumor microenvironment confirmed an enrichment of luminal epithelium corresponding with a decrease in basal and myoepithelium in LAR TNBC tumors. Increased immunosuppression in LAR patients may lead to a decreased presence of cycling T-cells and plasma cells. While, an increased presence of myofibroblast-like cancer-associated cells may impede drug delivery and treatment. In summary, the lower levels of tumor infiltrating lymphocytes (TILs), reduced immune activity in the micro-environment, and lower pCR rates after NAC, suggest that new therapeutic strategies for the LAR TNBC subtype need to be developed.

Abstract Biallelic mutations in Fanconi anemia complementation group genes disrupt DNA repair and result in the complex Fanconi anemia phenotype. In addition, germ line mutations in the BRCA2/FANCD1 Fanconi anemia complementation group gene have also been implicated in predisposition to a number of cancers including pancreatic cancer. The recent identification of FANCC and FANCG mutations in resected pancreatic tumors selected for loss of heterozygosity on chromosome 9, some of which were present in the germ line DNA, suggests that inactivation of these and other Fanconi complementation group genes may contribute to pancreatic cancer. To further assess the relevance of FANCC and FANCG mutations to pancreatic cancer we conducted a mutation screen of these genes in DNA from blood of 421 sequentially collected pancreatic cancer cases diagnosed at the Mayo Clinic. Two truncating FANCC mutations but no truncating FANCG mutations were identified in young onset (<55 years) pancreatic cancer cases with no family history of pancreatic cancer. Both mutations were associated with loss of heterozygosity of the wild-type allele in corresponding pancreatic tumors. In addition, no truncating mutations were identified in germ line DNA from blood of 658 control individuals undergoing routine colonoscopy. Taken together these data support the assertion that inherited mutations in FANCC can predispose to pancreatic cancer.

Abstract The influence of germ line BRCA2 unclassified variants (UCV), including missense mutations and in-frame deletions and insertions on BRCA2 function and on cancer risk, has not been defined although these mutations account for 43% of all identified BRCA2 sequence alterations. To investigate the effects of UCVs on BRCA2 function, we compared mutant and wild-type forms of BRCA2 using assays of cellular survival and viability, homologous recombination repair, and genome instability. We confirm that the effects of known deleterious mutations can be distinguished from neutral polymorphisms and wild-type BRCA2 in these assays, and we characterize the influence of a series of UCVs on BRCA2 function. We also describe how the results from the assays can be combined with data from analysis of cosegregation of the UCVs with cancer, co-occurrence of the UCVs with other deleterious mutations, and interspecies sequence variation in a comprehensive framework in an effort to better distinguish between disease predisposing and neutral UCVs. This combined approach represents a useful means of addressing the functional significance and cancer relevance of UCVs in BRCA2.

Abstract Introduction: Patients at extremes of age may be particularly vulnerable to poor physical and mental health after treatment for breast cancer; we examined factors associated with poor health in older breast cancer survivors. Methods: The Mayo Clinic Breast Disease Registry (MCBDR) is a prospective longitudinal cohort study that enrolls Mayo Clinic Rochester patients diagnosed with stage 0-4 breast cancer (BC). In 2020, we mailed a survey to 1,273 MCBDR participants aged 77+. Three PROMIS-10 items were used to assess overall health, mental health, and physical function. Self-reported comorbidities were also collected. Multivariate logistic regression analysis was used to identify significant (p<0.05) predictors of overall health, mental health, and physical function. Independent variables included demographics, clinical characteristics, and comorbidities. Results: 848/1273 MCBDR participants (67%) responded, 842 reporting their overall health. Median age at survey return was 82 years (range 77-100), and the median time since cancer diagnosis was 12 years. Excellent or very good overall health, mental health, and physical function were reported by 48%, 63.5%, and 77.1%, respectively. Older age was associated with poorer self-reported overall health, as were heart disease, diabetes, and lung disease, reported by 18%, 14%, and 7%, respectively (p<0.05 for all; see Table). Only heart disease was statistically significantly associated with poorer mental health (p=0.03). Physical function was reportedly better in survivors without a history of diabetes, stroke, or lung disease (p<0.05 for all), and in those who were closer to their cancer diagnosis (p=0.03). Tumor characteristics were not associated with overall health, mental health, or physical function. Conclusions: Comorbidities are common and impact self-reported overall health, mental health, and physical function in older breast cancer survivors. Table: Multivariate logistic regression model for overall health Overall health self-reported as excellent or very good No Yes Total p-value (N=437) (N=405) (N=842) Age at survey (years) <.001 Mean (SD) 82.8 (4.22) 81.7 (3.85) 82.3 (4.08) Median (range) 82.0 (77.0, 96.0) 81.0 (77.0, 100.0) 82.0 (77.0, 100.0) Years from cancer diagnosis to survey 0.708 Mean (SD) 12.1 (5.16) 11.8 (5.47) 11.9 (5.31) Median (range) 12.2 (3.1, 36.9) 11.5 (3.1, 36.4) 12.0 (3.1, 36.9) T stage T2 or higher, n (%) 0.276 No 357 (81.7%) 337 (83.2%) 694 (82.4%) Yes 80 (18.3%) 68 (16.8%) 148 (17.6%) N stage N1 or higher, n (%) 0.185 No 376 (86.0%) 339 (83.7%) 715 (84.9%) Yes 61 (14.0%) 66 (16.3%) 127 (15.1%) M stage M1, n (%) 0.313 No 434 (99.3%) 404 (99.8%) 838 (99.5%) Yes 3 (0.7%) 1 (0.2%) 4 (0.5%) Race, n (%) 0.460 Non-White 13 (3.0%) 8 (2.0%) 21 (2.5%) White 424 (97.0%) 397 (98.0%) 821 (97.5%) Heart disease, n (%) <.001 No 334 (76.4%) 353 (87.2%) 687 (81.6%) Yes 103 (23.6%) 52 (12.8%) 155 (18.4%) High blood pressure, n (%) 0.376 No 168 (38.4%) 188 (46.4%) 356 (42.3%) Yes 269 (61.6%) 217 (53.6%) 486 (57.7%) Stroke, n (%) 0.195 No 407 (93.1%) 392 (96.8%) 799 (94.9%) Yes 30 (6.9%) 13 (3.2%) 43 (5.1%) Diabetes, n (%) <.001 No 355 (81.2%) 370 (91.4%) 725 (86.1%) Yes 82 (18.8%) 35 (8.6%) 117 (13.9%) Lung disease, n (%) 0.023 No 394 (90.2%) 386 (95.3%) 780 (92.6%) Yes 43 (9.8%) 19 (4.7%) 62 (7.4%) Liver disease, n (%) 0.345 No 425 (97.3%) 401 (99.0%) 826 (98.1%) Yes 12 (2.7%) 4 (1.0%) 16 (1.9%) Kidney disease, n (%) 0.240 No 408 (93.4%) 392 (96.8%) 800 (95.0%) Yes 29 (6.6%) 13 (3.2%) 42 (5.0%) Citation Format: Dhauna Karam, Robert A. Vierkant, Shawna Ehlers, Rachel A. Freedman, Nicole Larson, Charles L. Loprinzi, Fergus Couch, Janet Olson, Kathryn J. Ruddy. Physical function, mental health, and overall health of older breast cancer survivors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5262.