Nicotine Vaping Causes Lungbr Cancer in Mice, Study Finds.br A recent study by New York Universitybr has found a pattern of lung cancer inbr mice exposed to e-cigarette vapor. .br Over a 54 week period, 40 mice receivedbr the vapor equivalent of someone who’sbr smoked e-cigarettes for three to six years. .br 22.5 percent developed lung cancer and 57.5 percentbr developed pre-cancerous lesions in their bladders.br An additional 20 mice,br who only received vaporbr free of nicotine, werebr found to be cancer free. .br According to the study’s lead professor,br Moon-shong Tang, these results prove thatbr e-cigarette vapor is likely a human carcinogen. .br The carcinogenic mechanism is via productionbr of nitrosamines, the proven human carcinogens.br So, the probability that e-cigarette vapor is abr human carcinogen is high, Moon-shong Tang, to Axios.br In a previous study, Tang also found thatbr electronic cigarette smoke induced DNAbr damage and inhibited DNA repair in mice.