The expression of p53 is what sets the two cell lines apart, with MCF-7 being shown to generally express wt p53 and MDA-MB-231 expressing mt p53.8 From the initial studies, we evaluated the expressional pattern of RBBP6 in cancer tissues and, as indicated in Figures 1 and 2, RBBP6 was variably expressed depending on the advancement of the cancer, with more advanced cancer expressing high levels of RBBP6 and moderate cancers expressing low levels of RBBP6. This evidence concerns the gene TP53 and cancer.