Here, we build upon previous studies demonstrating that the PI3K effector AKT regulates cellular H3K4 methylation through the phosphorylation of the H3K4 methyltransferase KMT2D/MLL4 (7) and the H3K4 demethylase KDM5A (6) in breast cancer. The gene discussed is PIK3CA; the disease is breast carcinoma.