* Cell growth and division: Normal cells have a complex system of signals that control when and how often they divide. Cancer cells ignore these signals and divide uncontrollably.
* Cell death (apoptosis): Normal cells undergo programmed cell death (apoptosis) when they are damaged or no longer needed. Cancer cells evade apoptosis, allowing them to survive and multiply.
* Cell differentiation: Normal cells mature and specialize into specific types of cells (e.g., muscle cells, skin cells). Cancer cells often lose their specialized function and revert to a more primitive state, allowing them to multiply rapidly and invade other tissues.
* Cell adhesion: Normal cells stick together in organized structures. Cancer cells often lose their ability to adhere to each other, allowing them to break away from tumors and spread to other parts of the body (metastasis).
* Immune system signals: Normal cells display signals that allow the immune system to recognize them as healthy. Cancer cells can suppress or evade the immune system, making them difficult to target for immune therapies.
* DNA repair: Normal cells have mechanisms to repair damaged DNA. Cancer cells often have defects in these mechanisms, leading to mutations that can further drive uncontrolled growth.
* Blood vessel formation (angiogenesis): Normal cells regulate the formation of new blood vessels to deliver oxygen and nutrients. Cancer cells can stimulate the growth of new blood vessels (angiogenesis) to provide them with the resources they need to grow and spread.
In essence, cancer cells become "rogue" cells that no longer follow the rules that govern normal cell behavior. This is why they are so dangerous and difficult to treat.
