KRAS and colonic neoplasm: Initially, in the experimental planning, we selected the cell lines HT-29, a K-ras wild type of primary colon cancer cell; SW480, a K-ras mutant type of primary colon cancer cell; Colo205, a K-ras wild type of metastatic colon cancer cell; and LoVo, K-ras mutant type of metastatic colon cancer cell.