Genomic characterization of somatic mutations by race and ethnicity in pancreatic cancer defined through AACR project GENIE

4138 Background: KRAS, TP53, SMAD4, and CDKN2A are widely recognized as the most common somatic mutations amongst patients with pancreatic ductal adenocarcinoma (PDAC); however, previous genomic studies have disproportionately included non-Hispanic White (NHW) patients with little to no inclusion of racial and ethnic minorities, particularly non-Hispanic Black (NHB) and Hispanic patients. Additionally, little is known about the distribution of KRAS point mutations in PDAC in specific racial and ethnic groups. Here, we describe somatic mutation differences in a larger and more racially and ethnically representative PDAC cohort than previously characterized. Methods: PDAC mutational data was downloaded from AACR Project GENIE (Genomics Evidence Neoplasia Information Exchange) v13.0, an international data registry of sequenced tumor samples from nearly 150,000 patients, on cBioPortal. PDAC cancer type was identified using OncoTree code. NHW, NHB, Hispanic (of any race), and Asian patients were then selected. Mutational frequency was calculated for all mutations. The primary objective was to compare the mutation frequencies between NHW and other races with respect to the most common mutations. To maximize power, we included any mutation with a frequency ≥5.0% where testing for mutation of that gene had been performed in at least 150 patients. Specific point mutations in KRAS were also extracted with stratification for racial and ethnic group. Fisher’s Exact Test was used to calculate the statistical significance of the differences in mutation frequency between NHW and minority groups. Results: Patients in the PDAC cohort included 5,292 individuals (NHW N = 4296, 80.7%; NHB N = 264, 5.0%; Hispanic N = 460, 8.7%; Asian N = 299, 5.7%). As compared to the NHW group, NHB patients had higher rates of TP53 (78.7% vs 69.0%, P = 0.0006) and PTPRT (5.3% vs 1.8%, P = 0.0095) mutations but fewer GNAS (0.4% vs 2.8%, P = 0.0097) mutations while Asian patients had higher frequency of ARID1A mutations (13.0% vs 8.8%, P = 0.024). KRAS G12D mutation was more prevalent in Hispanic patients (47.0% Hispanic vs 41.1% NHW, P = 0.0238), although rate of KRAS mutation overall was the same. Prevalence of KRAS G12C mutation was equivalent amongst all groups with an overall 1.6% frequency. Conclusions: Understanding the genomic landscape of PDAC is critical as we move towards increased use of targeted therapies to treat this disease. In this study, TP53, PTPRT, GNAS, and ARID1A mutations were shown to occur at different frequencies in specific racial and ethnic groups. G12D mutation of KRAS was disproportionately increased in Hispanics. These differences in molecular landscape amongst racial and ethnic groups could contribute to precision medicine strategies used to address this deadly disease.