In ovarian cancer cells, however, PIK3CA gain-of-function mutations and PTEN deficiency were correlated with their response to PI3K pathway inhibitors (Ihle et al., 2009; Di Nicolantonio et al., 2010; Meuillet et al., 2010; Santiskulvong et al., 2011; Tanaka et al., 2011; Meric-Bernstam et al., 2012). This evidence concerns the gene PIK3CA and ovarian cancer.