Abstract 4620: Somatic mutation profile of gastric cancer cases from the Hispanic population

Abstract

Abstract Gastric cancer contributes to a significant health care burden, being the third most common cause of cancer related deaths worldwide. In the US, gastric cancer incidence and mortality in the Hispanic population is more than double compared to Non-Hispanic whites (NHW). However, a majority of the large-scale gastric cancer genome characterization studies that have been carried so far have been largely limited to non-Hispanic (NH) populations, predominantly Non-Hispanic Whites (NHW). This “mono-ethnic” approach is likely to miss driver mutations that are unique or common in Hispanics but rare in NHWs and can lead to future genomic-driven cancer health disparities. Identification of driver mutations is important to understand the molecular basis of tumorigenesis and to develop better preventive and therapeutic strategies in minority groups like Hispanics. Therefore, the purpose of this study was to characterize gastric cancer somatic changes in the understudied Hispanic population. Somatic mutations were identified using whole exome sequencing (WES) of 36 tumor-normal pairs from Hispanic gastric cancer patients. Microsatellite stability tasting was also performed on all the samples and samples were divided into 27 microsatellite stable (MSS) and 9 microsatellite instable (MSI) cases. Interestingly, preliminary analysis of exome sequencing data delineates differences in mutational profile in our study population compared to publish studies in NH. For example, we found that the frequency of TP53, the most commonly mutated gastric cancer driver in NHs, had a significantly lower frequency in our Hispanic sample (33% in MSS tumors and 11% in MSI tumors compared to 50% in MSS and 35% in MSI tumors reported in TCGA dataset). Similar differences were also found in other frequently mutated gastric cancer genes, which suggest that the genetic pathways leading to gastric cancer in Hispanics are likely to be different to the ones involved in NHW tumors. In summary, our sequencing study of Hispanic gastric cancer cases have identified important differences with other populations, are likely to identify novel cancer drivers in this tumor type and would help bridge the gap in heath care disparities Citation Format: Rodrigo Prieto-Sanchez, Ruta Madhusudan Sahasrabudhe, Paul Lott, Mabel Bohorquez, Jhon Jairo Suarez, Gilbert Mateus, Javier Torres, Magdalena Echeverry, Luis Carvajal-Carmona. Somatic mutation profile of gastric cancer cases from the Hispanic population. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4620. doi:10.1158/1538-7445.AM2015-4620