Prevalence and Distribution of Unexpected Actionable Germline Pathogenic Variants Identified on Broad-Based Multigene Panel Testing Among Patients With Cancer.

Purpose: In patients with a variety of malignancies undergoing multigene panel testing (MGPT), we examined the frequency of a pathogenic/likely pathogenic variant (PV) that would not have been predicted on the basis of the patient's personal and family history of cancer.

Methods: This is a retrospective review of patients with cancer ascertained from a single academic cancer center who underwent broad-based MGPT of ≥20 cancer predisposition genes not selected on the basis of personal or family cancer history from 2015 to 2021. Low-penetrance variants and recessive inheritance genes were excluded.