Germline genetic variants were interactively associated with somatic alterations in gastric cancer

Genome-wide association studies have identified several germline variants in gastric cancer. Meanwhile, sequencing studies have characterized extensive somatic alterations that arise during gastric carcinogenesis. However, the relationship between the germline variants and somatic alterations is still unclear in gastric cancer. A total of 11 susceptibility loci and 276 driver genes of gastric cancer were determined based on previous studies and publicly available database. An enrichment analysis was made to detect whether driver genes were enriched in susceptibility regions. Besides, we performed a pathway enrichment analysis to find common-enrich pathways of cancer driver genes and susceptibility genes. Finally, on the basis of the gastric cancer samples and data from TCGA STAD project, we evaluated the associations between susceptibility loci and somatic alterations. Enrichment analysis showed that gastric cancer susceptibility genes were more likely to be enriched in driver genes than in all the genes (P = .05). The susceptibility genes and driver genes were commonly enriched in 8 biological pathways. Gastric cancer susceptibility locus of rs2285947 was associated with truncation mutation within Signaling by PDGF pathway (OR = 0.26, 95%CI: 0.12-0.55, P = 3.93 × 10^-4 ). The rs1679709 was connected with COSMIC Signature15 (P = .026). Moreover, rs1679709 was also associated with copy number values of RFC4 which is related to Signature15. These results provide evidence for the relationship between germline variants and somatic alterations, which facilitate understanding the interactive mechanism of germline variations with somatic alterations in gastric cancer development.