ERBB2 and colorectal cancer: For instance, the frequency of PIK3CA mutations is estimated to be 20–46% in ovarian clear cell carcinoma6,7, 12–40% in endometrioid carcinoma7, 13–28% in colorectal cancer, 14–23% in cervical cancer2,8, and up to 40% in hormone receptor positive/human epidermal growth factor receptor 2 (HER2) negative (HR+/HER2–) breast cancer9,10.