PIK3CA and nonpapillary renal cell carcinoma: Conversely, mutations in certain driver genes, including BAP1 (BRCA1 associated protein-1), PTEN (phosphatase and tensin homolog), PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha), SETD2 (SET domain containing 2) and TP53 (encoding tumor protein p53), were always subclonal, and thus probably involved in ccRCC progression.