PIK3CA and breast cancer: Conversely, in the single‐armed phase II NeoATP trial, in which four cycles of trastuzumab, pyrotinib, and paclitaxel‐cisplatin chemotherapy were offered in stage II‐III HER2 positive breast cancer patients in neoadjuvant setting, the pCR rate was comparable in patients with or without PIK3CA mutations (69.2% vs.