Furthermore, patients in the LCAC4TCGA subgroup exhibited significantly higher mutation rates in genes such as FAT3, SACS, TRPS1, PCDH15, VPS13B, GLI3, LRRK2, and RELN. Conversely, patients in the LCAC3TCGA subgroup had lower mutation burdens in most genes but had the highest mutation burdens in APC and TP53. This suggested that mutant APC and TP53 may serve as key driver genes in the carcinogenesis of this group, which exclusively consisted of patients with rectal cancer. This evidence concerns the gene PCDH15 and rectal cancer.