Genomic and transcriptomic analysis of Korean colorectal cancer patients

Background Colorectal cancer (CRC) is the third most common type of diagnosed cancer in the world and has the second-highest mortality rate. Meanwhile, South Korea has the second-highest incidence rate for CRC in the world. Objective To assess the possible influence of ethnicity on the molecular profile of colorectal cancer, we compared genomic and transcriptomic features of South Korean CRCs with European CRCs. Methods We assembled a genomic and transcriptomic dataset of South Korean CRC patients (KOCRC; n = 126) from previous studies and European cases (EUCRC; n = 245) selected from The Cancer Genome Atlas (TCGA). Then, we compared the two datasets in terms of clinical data, driver genes, mutational signature, gene sets, consensus molecular subtype, and fusion genes. Results These two cohorts showed similar profiles in driver mutations but differences in the mutation frequencies of some driver genes (including APC, TP53, PABPC1, FAT4, MUC7, HSPG2, GNAS, DENND5B, and BRAF ). Analysis of hallmark pathways using genomic data sets revealed further differences between these populations in the WNT, TP53, and NOTCH signaling pathways. In consensus molecular subtype (CMS) analyses of the study cases, no BRAF mutations were found in the CMS1 subtype of KOCRC, which contrasts with previous findings. Fusion gene analysis identified oncogenic fusion of PTPRK - RSPO3 in a subset of KOCRC patients without APC mutations. Conclusions This study presents insights into the genomic landscape of KOCRCs and reveals some similarities and differences with EUCRCs at the molecular level.