In order to assess the in vivo consequences of the ectopic expression of the CD44 and NUMB isoforms on the capacity of colon cancer cells to form metastatic lesions in the liver, parental HCT116 and SW480 cells and their CD44s-, CD44v6-, NUMB1/3-, and NUMB1/4-overexpressing (OE) counterparts were injected in the spleen of immune-incompetent recipient mice. The gene discussed is NUMB; the disease is malignant colon neoplasm.