What is cancer characterized by?

Cancer is fundamentally characterized by the uncontrolled growth of abnormal cells. This uncontrolled growth occurs when the regulatory mechanisms that typically control cell division and death fail, leading to the proliferation of cells that do not function normally. These abnormal cells can invade surrounding tissues and may spread to other parts of the body through the bloodstream and lymphatic system, a process known as metastasis.

The nature of cancer means that it can take many forms, and while tumors are a common characteristic of many cancers, not all cancers result in a visible tumor. For example, cancers such as leukemia arise from abnormal growth of blood cells without forming solid tumors. Additionally, cancer does not imply that the body will reject all treatments; many treatment options exist, including surgery, chemotherapy, and radiation therapy, which aim to control or eliminate the cancerous cells. Immediate recovery of damaged genes is not a typical characteristic of cancer either, as genetic mutations often contribute to cancer development rather than being repaired immediately.