TNC and in situ carcinoma: To confirm the expression and location of TNC in CRC tissues, we detected the expression of TNC using immunohistochemistry in 30 cases of non-neoplastic colonic mucosa (NCM), 30 cases of adenomatous colorectal polyps (AD), 30 cases of colorectal carcinoma in situ (CIS) and 50 cases of invasive colorectal carcinoma (ICC).