PIK3CA and breast cancer: Several phosphoproteins within the PI3K-AKT pathway analyzed by the Intracellular Signaling Protein Panel were within the low to average quartiles of the BC and TNBC cohorts, such as phospho-AKT, phospho-PDK1, and phospho-PRAS40, while phospho-GSK3β was above average in both cohorts (Fig. 3, box plots under “PI3K-AKT Pathway”).