A recent study consistent with our assumption demonstrated that the invasive depth of early CRC was fundamentally evaluated by colonoscopic examination combined with chromoendoscopy.[30] We also found that the expressions of Topo II and P-gp in the muscular layer and the serous layer were significantly higher than that in the mucosal layer and the submucosal layer (P < .05). This evidence concerns the gene PGP and colorectal carcinoma.