Research so far shows that legal e cigarettes are far less harmful than smoking, and can be an effective way of helping people who smoke to quit. However, there isn't enough research yet E Cigarette Vapor Linked to Lung Cancer in Mice Use of e cigarettes after quitting smoking increases lung cancer risk Cancerworld Magazine E Cigarettes Promote Macrophage Tumor Cells Crosstalk: Focus on Breast Carcinoma Progression and Lung Metastasis Evidence update on the cancer risk of vaping e cigarettes: A systematic review