PIK3CA and cancer: Here, based on the 34 core target genes, 20 significant signaling pathways (Fig. 4) with p < 0.01 were picked out for further analysis, including pathways in cancer (hsa05200), endocrine resistance (hsa01522), EGFR tyrosine kinase inhibitor resistance (hsa01521), and PI3K-Akt signaling pathway (hsa04151) as the top ones.