PIK3CA and endometrial cancer: Several major pathways that were identified in endometrial cancer,, such as hypoxia-inducible factor 1 alpha (HIF-1α)/VEGF, PI3K/AKT/mTOR, Ras/Raf/MEK/ERK, Wnt/β-catenin, and Insulin/Insulin growth factor-1 (IGF-I) signaling pathways (Figure 1).