MYC and breast carcinoma: Indeed, inhibition of the MEK/ERK pathway in v-Ki-ras rat fibroblasts, MDA-MB231 and HBC4 breast cancer cell lines, and c-Myc depletion by siRNA in MCF7 and over-expression of a c-Myc antagonist, Mxi1, in prostate carcinoma DU145, all induce reversion of the malignant phenotype [9-12].