E cigarettes Found to Cause Change in Mouth Bacteria Which Could Lead to Gum Disease or Oral Cancer Respiratory Therapy Vaping Leads Lung Disease Cancer Lungs : image vectorielle de stock (libre de droits) 2588641363 Shutterstock Scientists Warn: Vaping Likely Causes Cancer Many students believe that vaping harmless, which is far from the truth. Vape pens can contain potentially harmful substances such as chemicals linked to lung disease, cancer causing chemicals, heavy metals such as Former Smokers Who Vape at Greater Risk of Lung Cancer RT E Cigarettes and Vaping OHSU