KRAS and non-small cell lung carcinoma: While results from this study suggest a functional role for p53 in regulating the levels of mBDNF and proBDNF in NSCLC, it is important to note that although A549 cells are p53-positive and H1299 cells are p53-null, the A549 cell line carries a KRASG12S mutation and is of epithelial origin, whereas the H1299 cell line expresses a KRAS WT and is of mesenchymal origin [60,61,62].