Cancer is caused by genetic changes that lead to uncontrolled cell growth and the formation of tumors. These genetic mutations can arise from a combination of inherited factors and environmental exposures. The transformation of normal cells into cancer cells is a multi-stage process influenced by:
- Physical carcinogens such as ultraviolet (UV) and ionizing radiation
- Chemical carcinogens including tobacco smoke, asbestos, alcohol, certain food contaminants like aflatoxin, and arsenic in drinking water
- Biological carcinogens such as infections from specific viruses (e.g., human papillomavirus, hepatitis B and C viruses, Epstein-Barr virus), bacteria (e.g., Helicobacter pylori), and parasites
Several lifestyle and environmental risk factors are linked to increased cancer risk, including tobacco use, alcohol consumption, unhealthy diet, physical inactivity, and exposure to air pollution. Chronic inflammation and aging also contribute to the accumulation of genetic mutations that can lead to cancer development. Gene mutations can cause cells to grow uncontrollably, fail to stop growing when needed, and make errors when repairing DNA. While some mutations are inherited, most occur after birth due to exposure to carcinogens or random errors during cell division. Infections can directly increase cancer risk by causing chronic inflammation or introducing carcinogenic substances in the body. For example, HPV increases cervical cancer risk, hepatitis viruses increase liver cancer risk, and certain bacterial or parasitic infections are linked to gastrointestinal cancers. Overall, cancer is a complex disease caused by the interplay of genetic predispositions and multiple environmental and lifestyle factors that damage DNA and disrupt normal cell regulation mechanisms. Reducing exposure to known carcinogens and adopting healthy lifestyle habits can lower the risk of developing many cancers. This comprehensive understanding is based on current research and health authorities such as the World Health Organization and major cancer research institutions.
