MYC and breast cancer: The individual expression of the constitutively active mutants, Myc-tagged CDC42 (Myc-CDC42(F28L)), Myc-CDC42b(F28L), or the carboxyl terminally V5-tagged ACK (ACK-V5) did not affect the expression of either mTOR or the EGFR in MDA-MB-231 breast cancer cells (Fig. 1A, lanes 1–4, Fig. 1, B and C, columns 1–4).