PTEN and breast cancer: When counted together, 71.8% of breast cancers, which include 42.1% PPAPA and 29.7% PPAPA/TP53I tumors, contain the PTEN-PI3K-AKT1 pathway activated by genomic alterations of Pten, PIK3CA (H1047R & E545K), and AKT1 (E17K).