PIK3CA and breast cancer: The dual PI3K/mTOR inhibitor NVP-BEZ235 potently inhibited S6 phosphorylation, a well-defined downstream target of both PI3K and mTOR in the PI3K/AKT signalling pathway, consistent with a study by Serra et al (2008); in which S6 phosphorylation was suppressed by NVP-BEZ235 in the BT474 and SKBR3 breast cancer cell lines with varying potency.