To explore the molecular mechanisms underlying the anticancer effect of AdoMet in CRC cells and to evaluate if the modulation of P-gp is involved in AdoMet-induced resistance to 5-FU, we performed a qRT-PCR analysis of P-gp after 24 h incubation of HCT 116p53+/+ and LoVo cells with 50 μM 5-FU, with and without 48 h pretreatment with 500 μM AdoMet. This evidence concerns the gene PGP and colorectal carcinoma.