Cancer is a complex group of diseases characterized by the abnormal growth and division of cells that can invade and destroy normal tissues. It arises from genetic mutations or changes in the DNA of cells, leading to uncontrolled cell growth.

The immune system plays a crucial role in detecting and eliminating abnormal cells, including cancer cells, through a process called immuno-surveillance.

Normally, the immune system can recognize and destroy cancer cells before they develop into a tumor. However, cancer cells can sometimes evade or suppress the immune system, allowing them to grow and spread.

This is why it is so important for cancer patients receive complex treatment.