PIK3CA and neoplasm: The response (change in tumor volume at day 28 after starting treatment, or last time point if <28 days) in each PDX (n = 1 per model per treatment22) was stratified by MAP3K1 alterations (mutations or deletions), PIK3CA mutations, or luminal A status versus Luminal B versus all others, as predicted by a scaled-data correlation (RNAseq FPKM) to the PAM50 centroids (Fig. 4).