BCAT2 and neoplasm: The NSCLC tumours displayed increased expression of BCATm.23 These studies strongly suggest that BCAAs are important nitrogen sources for amino acid and nucleotide biosynthesis in cancer cells but cannot fully explain the correlation between the build-up of BCAAs and the reduction of tumour growth in BCATmKO mice, or the toxic growth effect of high leucine concentrations observed in EL-4 cells.