HRASLS4 is homologous with HRASLS3/H-rev107 [35, 36] and, like that enzyme, has reduced expression in a wide variety of primary human tumours, including lymphoma, ureter, kidney, rectal, and uterine, and cancer cell lines, including HL-60 promyelocytic leukemia cells, HeLa cells, K-562 chronic myelogenous leukemia cells, SW480 colon carcinoma, A549 colon carcinoma, and G361 melanoma cells [35]. This evidence concerns the gene PLAAT4 and colon carcinoma.