The PI3K/PTEN/Akt/mTOR and Raf/MEK/ERK pathways differed in their abilities to modulate the induction of cellular senescence in response to doxorubicin treatment in breast cancer cells as activated Akt-1 impeded senescence while activated Raf-1 did not, similar to the results of the present study. This evidence concerns the gene MAPK1 and breast cancer.