With respect to breast cancer subtypes, 100/263 (38.0%) HR-positive HER2-positive, 85/220 (38.6%) HR-negative HER2-positive, 1,857/2,549 (72.9%) HR-positive HER2-negative, and 1,516/18,63 (81.4%) TNBC samples had at least one alteration in the PIK3CA-AKT1-PTEN pathway (Figure 1). Here, PIK3CA is linked to breast cancer.