One of the major public health problems is cancer. Globally, colorectal cancer is the fourth common cancer in men and the third common cancer in women. Resistance to chemotherapy limits the effectiveness of chemotherapeutic treatment, where most of tumoral cells become insensitive to many drugs with different structure and function, this phenomenon is recognized as multi drug resistance (MDR). Several mechanisms for drug resistance have been suggested including mutation and over expression of the drug’s target, inactivation and efflux the drug from the cell by ATP Binding Cassette transporters . ATP-binding cassette (ABC) transporters are a family of transporter proteins with ability to transport a range of substrate molecules across membranes . Molecular investigations on drug resistance have led to the discovery of genes coding for Multidrug resistance1 (MDR1), multidrug resistance-associated protein 1 (MRP1) . MDR1 protein or P-gp is a transmembrane glycoprotein with molecular weight of 170 kDa, encodes by MDR gene.