PIK3CA and malignant colon neoplasm: The profiles of key mutation genes in colon cancer, such as TP53, KRAS, SYNE1, PIK3CA, BRAF, FAT4, CSMD3, CTNNB1, and RYR2, were selected, and the mutation frequencies of the SYNE1, CSMD4, and BRAF genes in the C1 subtype were higher than those in the C2 subtype, whereas the mutation frequencies of TP53 (Mirgayazova et al., 2019), KRAS, PIK3CA, and FAT4 in the C1 subtype were lower than those in the C2 subtype (Figures 3A,B).