Approximately 30% of endometrioid endometrial cancers harbor mutations or amplification in the catalytic subunit of PI3K, PIK3CA, whereas EGFR overexpression is associated with poor prognosis of endometrial cancer2,21–23, and the growth-inhibitory actions of PI3K or EGFR inhibitors on Hec-1A endometrial cancer cells have reported24–28. Here, PIK3CA is linked to endometrial cancer.