NER genes, such as XPA, XPC, XPG, XPF, XPD, and ERCC1, were measured in normal and cancerous human colorectal tissues belonging to the first section of the clinical trial and the results showed that only XPC mRNA level in the colorectal cancer tissues was significantly increased compared with the corresponding normal tissue (P < 0.01). The gene discussed is ERCC4; the disease is colorectal cancer.