PIK3CA and uterine corpus endometrial carcinoma: 753 out of 11,904 patients (6.33%) had PIK3CA mutations, with the highest mutation frequencies being detected in breast invasive carcinoma (BRCA), cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC), SCL, and uterine corpus endometrial carcinoma (UCEC) (Fig. 1A).