BCAT1 and nonpapillary renal cell carcinoma: Given that BCAAs, especially leucine, serve as vital signaling molecules in the PI3K/AKT/mTOR pathway and can activate it in conjunction with growth factors [43, 44], our hypothesis posits that high BCAT1 expression may activate the PI3K/Akt/mTOR pathway via the production of essential BCAAs, consequently enhancing ccRCC angiogenesis.