Tumorigenesis is the process by which normal cells transform into cancerous cells. This transformation typically involves a series of genetic mutations that disrupt normal cell functions, leading to uncontrolled cell growth and division. Factors such as environmental influences, genetic predisposition, and lifestyle choices can contribute to these mutations. As cells continue to multiply, they can form a mass known as a tumor. Tumors can be classified as benign, which are non-cancerous and do not spread, or malignant, which are cancerous and can invade nearby tissues or metastasize to other parts of the body. Understanding tumorigenesis is crucial for developing effective cancer treatments.