Mutational characteristics of young and elderly gastric cancer: a comparative study

BackgroundYoung gastric cancer (YGC) has been indicated as having a worse prognosis than in elderly gastric cancer (EGC). It has been reported that YGC and EGC patients show different genomic profiles; however, there has been no comparative study conducted to reveal their mutational characteristics.MethodsFirstly, we divided and analyzed the mutational landscape and 50 cancer-related genes characters of YGC (n=18) and EGC (n=18) patients from The Cancer Genome Atlas-Stomach Adenocarcinoma (TCGA-STAD). A total of 8 gastric cancer samples including 4 YGC and 4 EGC patients were collected to detect 50 cancer-related genes by multiplex polymerase chain reaction (PCR) next generation sequencing. The R/maftools package was used to describe the mutational characteristics.ResultsOur results showed that the EGC group harbored more mutations than the YGC group. In 50 cancer-related genes in our cohort, the YGC group tended to be different from the EGC group using multiplex PCR next generation sequencing. In the YGC group, candidate mutations were identified within the following genes: IDH2, PDGFRA, KRAS, FLT3, FGFR2, and FGFR3. The YGC group showed less tumor mutational burden (TMB) level then EGC.ConclusionsThe YGC group tended to be more sensitive to molecularly targeted therapy because of it having more somatic mutations in 50 cancer-related genes using targeted next-generation sequencing.