We observed that p-Akt levels were increased in SKBR3, MDA-MB-231, and primary breast cancer BC1205 and BC1302 cells following induction with high 5-FU concentrations (100 μM) and longer incubation times (6 d); conversely, phosphor-ERK1/2 levels were not significantly altered. The gene discussed is MAPK3; the disease is breast carcinoma.