LAUSR

Background: Invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) of the breast typically present distinct clinicopathological characteristics and responsiveness to systemic therapy. In addition, breast cancer data from The Cancer Genome Atlas (TCGA) have shown these two pathological subtypes also present distinct genomic features when analyzed using DNA copy number arrays and whole exome sequencing platforms. More recently, the AACR Project GENIE Consortium, which is a publicly accessible international cancer registry of real-world data assembled through data sharing among leading cancer centers in the world, have allowed in-depth analyses of clinical actionability using patient-level data from clinical next-generation sequencing (NGS) assays. In this study, we assessed the somatic mutational landscapes of a large cohort (n = 8,756) of invasive breast carcinomas from 19 institutions participating in the GENIE Consortium Cohort (v8.0) and examined clinical actionability of unique mutations identified in each breast cancer subtype. Method: We assessed the eighth data release of the GENIE Consortium Cohort encompassing targeted sequencing data from 7,647 IDC and 1,109 ILC cases. Clinical features and somatic mutations including single-nucleotide variants, small indels, fusions, and copy number alterations (CNAs) were retrieved from cBioportal and SAGE Bionetworks. Gene actionability was examined using both OncoKB and CiVIC publicly available knowledgebases. All patient samples were de-identified and encoded with GENIE sample codes. Results: Patients with IDC tumors were 5 years younger than patients with ILC tumors at the time sequencing data was reported (median 55 versus median 60 years old, Kruskal-Wallis, p Citation Format: Alessandro Leal, Patricia Taranto, Poliana BG Blasi, Carlos Tadeu Garrote, Fernando Moura. Somatic mutational landscapes of invasive ductal and lobular carcinomas in the GENIE consortium cohort: Real-world gene actionability assessment of 8,756 breast cancer patients [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS18-41.