Analyses of the clinical predictive factors for liver- or lung-only metastasis in patients with initial distant metastasis confined to a single organ (N = 113) were performed including other clinical variables [gender, age (< 65 vs. ≥ 65 years), clinical situations for the development of systemic metastasis (stage IV at the time of initial CRC diagnosis vs. recurred after curative resection of stage I - III CRC), primary tumor sites (colon vs. rectum), histologic grade, MSI, etc.] along with the KRAS status. This evidence concerns the gene KRAS and neoplasm.