It is shown that colorectal cancer can develop via multiple genetic (APC, KRAS, TP53, BRAF, MMR) and epigenetic (MLH1) factors involving several distinct but intertwined pathways, such as Wnt signalling pathway, Myc signalling pathway, MAPK pathway, TGF-β pathway, and serrated neoplasia pathway. Here, KRAS is linked to colorectal cancer.