PIK3R1 and endometrial endometrioid adenocarcinoma: The results showed that both PIK3CA mutations and PIK3R1 mutations were associated with endometrial endometrioid adenocarcinoma (EEA), compared with serous endometrioid adenocarcinoma (SEA) (OR = 1.9, 5.2 and p = 0.03, 0.00) (Figure 4D).