The correlation coefficient showed that CD133 was positively correlated with P-gp protein expression (r = −0.71, p < 0.001) (Fig. 2f) and MDR1 mRNA expression (r = −0.66, p < 0.001) (Fig. 2i) in the 38 cases of CRC. This evidence concerns the gene PROM1 and colorectal carcinoma.