We further analyzed correlation whether a combination of PIK3CA mutation status, AKT phospho-Ser473 (pAKT) and ERα phospho-Ser167 (pER) had any predictive function with regard to clinicopathological characteristics and disease-free survival in postmenopausal ER-positive, HER2-negative breast cancer (Table 7). This evidence concerns the gene PIK3CA and breast cancer.