PIK3CA and breast cancer: The maturation of the RNA cap involving guanosine N-7 methylation, catalyzsed by the HsRNMT (RNA guanine-7 methyltransferase (HsRNMT)-RAM (RNA guanine-N7 methyltransferase activating subunit (RAM) complex, is currently under investigation as a novel strategy to combat PIK3CA -mutant breast cancer.