PIK3CA and breast carcinoma: Several studies have shown that inhibition of the PI3K pathway induces the expression and phosphorylation of multiple RTKs, such as HER2, via the forkhead box O-regulated transcriptional process in breast cancer cells (Chandarlapaty et al., 2011; Garrett et al., 2011; O’Reilly et al., 2006; Tao et al., 2014).