PGP and colorectal carcinoma: S‐adenosylmethionine (AdoMet), a natural chemical and generally utilized as a dietary supplement, was capable of conquering 5‐FU chemoresistance in CRC cells through reverting the P‐gp upregulation induced by 5‐FU and suppressing the activation of the key anti‐apoptotic factor NF‐κB implicated in P‐gp‐related chemoresistance.25