CCND1 and adenoma: Arber and colleagues (1997) studied the expression of CCND1 in normal colonic mucosa, adenoma, and adenocarcinoma and confirmed its high expression in colonic tumors, thus indicating CCND1 expression as an early event during multistage process of CRC tumorigenesis that may deregulate cell-cycle control in benign adenomas and stimulate tumor progression [69].