TP53 and lung cancer: Even though nicotine-induced proliferation of lung cancer cells has been reported [4], our findings show for the first time that, among the lung cancer cell lines, nicotine induces more proliferation in H1299 lacking p53 especially at lower concentrations (10-9M -10-7M) than A549 with active p53 (maximum at 10-7M -10-6M).