PIK3CA and breast cancer: Therefore, we conducted a hospital-based case-control study of 920 BC patients and 908 cancer-free controls to evaluate associations between SNPs rs701848 located in the 3′UTR of PTEN, PIK3CA rs2699887, and rs2494752 located in the 5′UTR of AKT1 and breast cancer risk and response to CE(A)F regimen and clinical outcomes in a Chinese Population.