Mouth cancer is primarily caused by changes in the DNA of cells in the mouth, which leads to uncontrolled growth and formation of cancerous tumors. The main risk factors include using tobacco (cigarettes, cigars, pipes, chewing tobacco, snuff), heavy and frequent alcohol consumption, excessive sun exposure to the lips, infection with the human papillomavirus (HPV), and a weakened immune system. Genetic predisposition and poor nutrition may also contribute. Tobacco and alcohol used together significantly increase the risk. HPV, particularly the HPV-16 type, is linked to cancers of the mouth and throat. Mouth cancer usually starts in squamous cells lining the lips and mouth. It mostly affects people over 40 and is more common in men, but anyone can be affected. Protecting lips from sun exposure, not using tobacco, limiting alcohol, vaccination against HPV, and regular medical/dental check- ups can help reduce risk.