Cancer cells are abnormal cells that grow and divide uncontrollably, unlike normal cells that follow a regulated life cycle. They can form masses called tumors, which can invade nearby tissues and disrupt normal bodily functions. Cancer cells can also spread to other parts of the body through the bloodstream or lymphatic system, a process known as metastasis. These cells often have mutations in their DNA that allow them to bypass the usual checks and balances that control cell growth. Factors such as genetics, environmental exposures, and lifestyle choices can contribute to the development of cancer cells, making prevention and early detection crucial for effective treatment.