What is Cancer?

Cancer causes around 8 million deaths annually and is not a single disease but over 200 types affecting various body parts. It originates from a single cell that undergoes DNA damage due to lifestyle or genetic factors. The body has mechanisms like DNA repair and apoptosis to prevent cancer, but if these fail, cells divide uncontrollably, forming tumors. Tumors can spread through metastasis, making early detection crucial for treatment.

Explain the concept of apoptosis and its significance in cancer.

What is metastasis and why is early detection important?