Transcriptomic analysis of colorectal carcinoma tissues from a Korean population.

As a disease with a high mortality rate, colorectal cancer (CRC) highlights the importance of comprehending its molecular mechanisms to develop effective therapies. In this study, we conducted RNA sequencing (RNA-seq) analysis on 476 samples consisting of fresh-frozen CRC tissues and adjacent normal tissues obtained from Samsung Medical Center (SMC) in South Korea. By analyzing gene expression differences, we identified that upregulated genes in tumor samples were significantly associated with pathways related to the cell cycle, extracellular matrix (ECM)-receptor interaction, and DNA damage response (DDR). Conversely, genes exhibiting high expression in normal samples were primarily related to metabolic pathways. Tumor samples were found to be enriched in various DDR pathways, prompting an investigation into the enrichment of related genes. Additionally, the analysis focused on the Homologous recombination (HR) pathway, for which the Homologous recombination deficiency (HRD) score was calculated. Furthermore, we categorized colorectal tumor samples into four subgroups using in silico methods to identify the biological and clinical characteristics of each subgroup and compared our results with those of the widely used existing subgrouping methods. Majority of our fibroblast and immune enriched/fibroblast samples aligned with CMS4, characterized by stromal invasion and mesenchymal differentiation, whereas the immune enriched subtype aligned with CMS1, known for its immune-centric profile. To investigate the clinical implications, the composition of the tumor microenvironment (TME) by cell type was examined across four subgroups, along with an immunological analysis. In particular, the calculated HRD score and the expression levels of immune-related genes associated with CRC were analyzed to provide evidence for personalized therapeutic strategies for each subgroup. Our findings provide valuable insights into the molecular mechanisms underlying CRC in Korean patients, particularly in the SMC patient group, and offer opportunities for personalized therapeutic strategies.