PIK3CA and head and neck squamous cell carcinoma: And according to the annotation result of CIViC, we found that PIK3CA amplification was associated with partial response to treatment with PI3K inhibitor pictilisib (GDC-0941) in epithelial ovarian cancer patients26, and positively associated with the sensitive of PI3K inhibitor in stomach carcinoma and head and neck squamous cell carcinoma (HNSCC)27,28.