We have previously performed an integrated analysis of the PI3K and interacting pathways in 243 endometrial cancer and showed that the PI3K pathway is activated in over 80% of endometrioid endometrial cancers by mutations in the PTEN (44%), PIK3CA (40%), PIK3R1 (20%) and PIK3R2 (5%) genes [4, 5]. Here, PIK3CA is linked to endometrial cancer.