How do some people get cancer?

Cancer is a complex disease that can arise from a combination of genetic mutations and external factors. It occurs when the body's cells begin to grow uncontrollably and divide to form a mass known as a tumor. There are several key factors that can contribute to the development of cancer: 1. Genetic Mutations: Some people inherit genetic mutations that make them more susceptible to developing cancer. These mutations can be passed down from parents or can occur spontaneously. 2. Tobacco Use: Smoking is the leading cause of preventable cancer. The chemicals in tobacco can damage the DNA within cells, leading to mutations that can cause cancer, particularly lung cancer. 3. Sun Exposure: Prolonged exposure to the sun's ultraviolet (UV) rays can cause damage to the skin cells, increasing the risk of skin cancer. 4. Unhealthy Lifestyle Choices: Poor diet, lack of physical activity, and excessive alcohol consumption can contribute to the development of certain cancers. 5. Infections: Certain viruses, such as human papillomavirus (HPV), hepatitis B and C (HBV, HCV), and the bacterium Helicobacter pylori, can increase the risk of specific types of cancer. 6. Environmental and Occupational Exposures: Exposure to certain chemicals, radiation, and other environmental factors can increase the risk of developing cancer. 7. Age: The risk of most types of cancer increases as people get older because the body's cells accumulate more mutations over time. 8. Sex and Hormonal Factors: Some cancers are more common in one sex than the other, and hormonal factors can play a role in the development of certain cancers, such as breast and prostate cancer. 9. Immunosuppression: A weakened immune system, due to diseases like HIV/AIDS or organ transplantation, can increase the risk of developing some types of cancer. 10. Obesity: Excess body weight has been linked to an increased risk of several types of cancer. It's important to note that not everyone who is exposed to these risk factors will develop cancer, and many people with cancer have no known risk factors. Cancer prevention and early detection are key to reducing the impact of the disease.

Some behavioral and environmental triggers can cause changes in the body's cells that push them into a cancerous state. For example, cigarettes are known to increase the risk of lung cancer. Too much exposure to the sun can increase the risk of skin cancer.