Multigene hereditary cancer testing in sarcoma patients.

Abstract

1518 Background: In multi-gene hereditary cancer testing, multiple syndromes may be interrogated simultaneously, increasing the likelihood of detecting an underlying cancer predisposition. We characterized the yield and distribution of pathogenic or likely pathogenic variants (PV/LPV) in patients with a personal history of sarcoma undergoing panel testing through our clinical diagnostic laboratory. Methods: We retrospectively reviewed panel test results, demographic data, and personal/family history information from patients reporting a personal history of sarcoma. Patients included in this study underwent panel testing (NGS and del/dup) of up to 61 genes at this laboratory and concurrent or prior TP53 analysis at this or an outside laboratory. Chi-square and Fisher’s exact tests were used to compare groups. Results: Among 374 sarcoma patients, 53 (14.2%) harbored one or more PV/LPV in 14 genes: TP53, BRCA2, CHEK2, BRCA1, ATM, MSH6, MLH1, NBN, BAP1, BRIP1, FLCN, MSH2, PTEN, and RB1. Thirty-nine (10.4%) individuals reported both a personal and family history of sarcoma; however, PV/LPV were not more likely to be detected among this group than those with personal history alone (p = 1.0). PV/LPV were most often detected in BRCA1/2 (15/374, 4.0%) or TP53 (12/374, 3.2%). Notably, four probands with BRCA1/2 PV/LPV reported a family history of sarcoma, including one kindred in which the variant was present in two brothers, both affected with sarcoma. Additionally, seven patients were found to have PV/LPV (1.9%) in genes causative for Lynch syndrome. Among patients with PV/LPV in genes other than TP53, nearly half (17/41, 41.5%) met National Comprehensive Cancer Network TP53 testing criteria. Conclusions: The majority of PV/LPV were identified in genes for which association with sarcoma risk is not well-established. While several of these genes have been implicated in somatic pathways related to sarcoma development, it is unclear whether these germline findings are causative, play no role, or modify sarcoma risk. Although these data do not inherently associate non- TP53 genes with sarcoma risk, they suggest a potential clinical benefit can be gained from performing hereditary cancer risk assessment and multi-gene panel testing in sarcoma patients.