Genomic landscapes of brain metastasis patients of colorectal cancer to reveal clinical potential of individualized therapies.

674Background: Brain metastasis (BM) from colorectal cancer (CRC) is rare with 0.6-2.9% incidence rising in decades partly due to improved systemic treatment and prolonged survival. CRC patients had poor prognosis after BM because of lack of effective therapy. Commonly, only isolated BM of CRC patients are candidates for surgery and decisions for individualized therapies in patients with BM are often made according to primary-tumor biopsies, however, whether genomic features were similar in BMs and in primary CRC remained unknown. Thus, it is urgent to describe the molecular landscapes of BM genomics and to identify potentially clinically informative alterations. Methods: We conducted whole-exome sequencing on 15 “trios” of patient-matched brain metastases, primary CRC tumors, and adjacent-normal samples. Sequencing data processing and analysis were performed using pipeline of GATK best practice. Mutect2 algorithm were used to identify somatic substitutions in targeted exons. Clonal Evolution Suite was ap...