PIK3CA and breast cancer: About 97% of breast cancers show one or more aneuploidies, where around 60% of breast cancer tumors contain an extra copy of chromosome arm 1q11, which is a more prevalent alteration compared to mutations in genes like PIK3CA (found in 39% of breast tumors) that encodes Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Alpha, or TP53 (in 34%) [145] which encodes p53 protein, a tumor suppressor.