As a field expert in oncology, I can provide you with a detailed explanation of the causes of cancer. Cancer is a complex disease that can arise from a variety of factors, both internal and external to the body. Here are some of the key causes: 1. Gene mutations: These are changes in the DNA sequence that can lead to the formation of cancerous cells. Not all gene mutations are inherited; many occur after birth as a result of exposure to certain factors. 2. Environmental factors: Exposure to harmful substances or conditions can cause gene mutations. This includes: - Tobacco smoke: A well-known cause of lung cancer and other types of cancer. - Radiation: Both ionizing radiation, such as that from X-rays or radioactive materials, and non-ionizing radiation, like that from cell phones, can potentially cause mutations. - Viruses: Certain viruses, like human papillomavirus (HPV) and hepatitis B and C, can lead to cancer under certain conditions. - Carcinogens: These are cancer-causing chemicals found in tobacco products, asbestos, certain pesticides, and more. 3. Lifestyle factors: - Obesity: Excess body weight has been linked to an increased risk of several types of cancer. - Hormones: Hormonal imbalances or exposure to certain hormones, especially over long periods, can increase the risk of hormone-related cancers. - Chronic inflammation: Persistent inflammation from conditions like ulcerative colitis can increase the risk of colorectal cancer. - Physical inactivity: A lack of exercise is associated with a higher risk of certain cancers, including those of the colon and breast. 4. Age: The risk of developing cancer increases as you get older because the body's cells accumulate more mutations over time. 5. Inherited genetic factors: While most gene mutations occur after birth, some individuals may inherit mutations that predispose them to cancer. 6. Alcohol consumption: Excessive alcohol intake is a risk factor for several types of cancer, including liver, mouth, and throat cancers. 7. Diet: A diet high in red meat and processed meats, and low in fruits and vegetables, can increase cancer risk. 8. Occupational exposures: Some jobs expose workers to carcinogens, increasing their risk of developing certain types of cancer. read more >>

Gene mutations that occur after birth. Most gene mutations occur after you're born and aren't inherited. A number of forces can cause gene mutations, such as smoking, radiation, viruses, cancer-causing chemicals (carcinogens), obesity, hormones, chronic inflammation and a lack of exercise.read more >>