The causes of lip cancer are frequently questioned. While it is not precisely clear what leads to the development of this type of cancer, there are many known risk factors. Generally, cancer begins as a result of changes (mutations) occurring in the DNA of cells; these mutations cause cells to multiply uncontrollably and lead to tumor formation. The main risk factors influential in the development of lip cancer are: the use of tobacco products (including cigarettes), excessive alcohol consumption, prolonged and unprotected exposure to sunlight, having fair skin, male gender, human papillomavirus (HPV) infection, and being over 40 years of age. These factors can increase the likelihood of genetic changes occurring in lip cells.