PIK3CA and neoplasm: One study noticed that amplifications of ERBB2, FGFR1, PIK3CA, and CDK8 genes were present in metastatic sites, and not in the paired primary tumor, suggesting that these amplifications, which facilitate signaling in pathways including MAPK, PI3K/AKT, and Wnt/β-catenin, may also have a role in tumor metastasis [35,36,40].