Causes of cancer

Cancer

Cancer is a complex group of diseases characterized by the uncontrolled growth and spread of abnormal cells. If not controlled, it can result in death. Cancer is caused by changes to DNA within cells, which can be inherited or result from environmental and lifestyle factors. Most cancers are related to environmental exposures that interact with the body. The term "environmental" encompasses a wide range of external factors, including biophysical elements like pollution or UV radiation, as well as lifestyle and behavioral aspects.

Microscopic view of cancer cell division.

Causes

Cancer arises from genetic changes that cause uncontrolled cell growth. These changes include:

• DNA damage: The primary cause of sporadic (non-familial) cancers, resulting from errors during cell division or exposure to carcinogens.
• Inherited genetic mutations: A minority of cancers are passed down genetically, increasing the risk of certain types of cancer.
• Environmental and lifestyle factors: Include exposures such as air pollution, smoking, diet, and UV radiation.

Illustration of DNA damage from carcinogens.

Types of Cancer

There are over 100 types of cancer, categorized by the type of cell that is initially affected. Common types include:

• Lung cancer
• Breast cancer
• Prostate cancer
• Colorectal cancer
• Skin cancer

Diagnosis

Cancer diagnosis typically involves:

• Physical examinations: Checking for abnormal masses or general signs of health.
• Laboratory tests: Blood, urine, and other bodily fluids are tested for abnormalities.
• Imaging tests: CT scans, MRIs, and X-rays help visualize tumors.
• Biopsy: Examination of a small tissue sample for cancer cells.

A biopsy procedure being performed.

Treatment

Treatment depends on the type, stage, and location of the cancer, as well as the patient's health and preferences. Common treatments include:

• Surgery: To remove tumors.
• Chemotherapy: Uses drugs to kill cancer cells.
• Radiation therapy: Uses high-energy rays to kill cancer cells.
• Immunotherapy: Boosts the body's natural defenses to fight cancer.
• Targeted therapy: Targets specific genes or proteins that contribute to cancer growth.

Environmental, Lifestyle, and Behavioral Factors

Cancer research emphasizes the role of environmental, lifestyle, and behavioral factors in cancer risk. Preventive measures include:

• Avoiding tobacco
• Maintaining a healthy diet
• Regular physical activity
• Limiting alcohol consumption
• Protecting skin from the sun

See Also

• Oncovirus
• Carcinogen
• Genomic instability
• Cancer prevention

References

• World Health Organization. (2020). Cancer.
• American Cancer Society. (2021). Cancer Facts & Figures 2021.

External Links

• World Health Organization: Cancer
• American Cancer Society