The causes of lip cancer are a frequently wondered topic. While the exact causes of lip cancer are not fully understood, there are specific factors that increase the risk of developing the disease. Generally, cancer begins as a result of genetic changes (mutations) occurring in the DNA of cells. These mutations lead to uncontrolled division and proliferation of cells. These rapidly multiplying abnormal cells come together to form masses called tumors. The main factors affecting the risk of lip cancer include: smoking and using other tobacco products, excessive alcohol consumption, prolonged and unprotected sun exposure, having light skin color, male gender, HPV (human papillomavirus) infection, and being over 40 years of age.