The NNK-treated group developed lung adenocarcinoma sooner than the saline-treated control group, an effect which was most likely enhanced by mutations in multiple genes, such as those for ATM, histone methyltransferase 2D (KMT2D), neurofibromatosis type 1 (NF1), transformation related protein 53 (Trp53), MET, and enhancer of zeste homolog 2 (Ezh2) [79, 80]. Here, TP53 is linked to lung adenocarcinoma.