PIK3CA and breast cancer: As shown in Fig 3C, among the top 1,469 genes higher in Tp53Indel/Pik3caH1047R tumors over Pik3caH1047R only tumors, 297 genes are also enriched in genes higher in TCGA breast cancer cases mutated for both TP53 (loss or point mutations) and PIK3CA (point mutations) when compared to cases mutated for PIK3CA but WT for TP53 (enrichment p value <1E-14, one-sided Fisher’s exact test).