Multidrug resistance protein 1 (P-glycoprotein or MDR1, gene symbol ABCB1) is highly expressed in healthy colorectal mucosa, polyps, and CRC cells [14], where it prevents the accumulation of a wide variety of drugs [47,48,49], thus contributing to the underlying mechanisms involved in chemoresistance [4,50,51]. The gene discussed is ABCB1; the disease is colorectal carcinoma.