PIK3CB and nonpapillary renal cell carcinoma: Finally, further WB analysis displayed that the protein expression levels of PI3K, AKT and mTOR were not significantly changed between ccRCC and normal specimens (P = 0.774, P = 0.585, P = 0.480, respectively; Fig. 4), which also consistent with the mRNA expression of PI3K/AKT/mTOR signaling members.