Definition:

Colorectal cancer (CRC) is the third most common malignancy diagnosed globally and the fourth leading cause of cancer-related death worldwide. CRC is a multifactorial disease involving genetic, environmental and lifestyle risk factors. Despite being strongly influenced by hereditary components, most CRC cases are sporadic and slowly develop over several years. Sequential accumulation of mutations in Wnt, EGFR, P53 and TGF-β signaling pathways leads to the initiation and progression of CRCs. Early APC gene mutations occurs in 70% of colorectal adenomas, most of which will progress to carcinoma by acquiring activating mutations in KRAS and subsequent inactivating mutations in TP53 and SMAD4.