To investigate the effect of C2-ceramide in inducing cell senescence and its association with p53 status, two different types of breast cancer cells, harbored wild-type p53 (MCF-7) and mutant p53 (MDA-MB231), were used in this study to further clarify the cell response of apoptosis and chemoresistance toward C2-ceramide. The gene discussed is TP53; the disease is breast cancer.