We first assessed the stand-alone toxicity of zerumbone in CRC cells and chose the radiosensitive, most sensitive to zerumbone HCT116 cells (wild-type p53; mutant k-RAS)28 and radioresistant, least sensitive to zerumbone HT29 cells (mutant p53; wild-type k-RAS)28 for further investigations. The gene discussed is KRAS; the disease is colorectal carcinoma.