NQO1 and colorectal carcinoma: Subsequent immunohistochemical (IHC) analysis of 93 paraffin-embedded CRC samples and 85 non-cancerous tissues confirmed that the NQO1 protein expression was conspicuously elevated in CRC tissues (Fig. 1E, P < 0.01), with increments being observed parallel to clinical stage progression and lymph node metastasis (Fig. 1F, P < 0.01).