Morphologic and molecular studies of the mouse tumors revealed their similarity to human colorectal tumors, suggesting that mice in which the CDX2P-NLS Cre transgene is used to target Apc (CPC-Apc), and other genes of interest such as K-ras and Tgfbrt2, simultaneously can be used for studies in colitis-induced colorectal cancer development. This evidence concerns the gene KRAS and colorectal neoplasm.