Cancer develops when certain cells in the body begin growing and dividing in an abnormal way. Normally, cells follow controlled processes that regulate growth, repair, and replacement. Cancer can occur when genetic changes interfere with these controls.
Genetic Changes and Cancer
Cells contain DNA that provides instructions for how they function. Changes in DNA can affect genes responsible for cell growth and division. Some genetic changes develop during a person’s lifetime, while others can be inherited from parents.
Uncontrolled Cell Growth
When important growth-control mechanisms are disrupted, abnormal cells may continue multiplying when they should stop. These cells can accumulate and sometimes form a mass known as a tumor. Not every tumor is cancerous, and some cancers do not create solid tumors.
Invasion and Metastasis
Some cancer cells can invade nearby tissues. In advanced disease, cancer cells may travel through the bloodstream or lymphatic system to other parts of the body. This process is called metastasis.
Factors That Can Increase Risk
Cancer risk can be influenced by factors such as tobacco use, certain infections, ultraviolet radiation, alcohol consumption, environmental exposures, inherited genetic changes, and increasing age. Risk factors vary depending on the cancer type.
Final Thoughts
Cancer is a complex group of diseases rather than a single condition. Understanding how abnormal cell growth occurs can provide a useful foundation for learning about cancer prevention, diagnosis, and treatment.