What is cancer? What is a tumor?

1 Answer
Jun 1, 2017

Cancer is a group of diseases involving abnormal cell growth forming tumors, with the potential to invade or spread to other parts of the body.


Normally, the body forms new cells as it needs them, replacing old cells that die. Sometimes this process goes wrong. New cells grow even when not needed and old cells don't die when they should.

A tumor is a group of cells that have undergone unregulated growth and will often form a mass or lump, but may be distributed diffusely. Tumors maybe benign ( not cancerous ) or malignant
( cancerous ).

The progression from normal cells to cells that can form a detectable mass to outright cancer involves multiple steps known as malignant progression.

Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss and a change in bowel movements. Over 100 types of cancers affect humans. Cancer treatment may include chemotherapy, radiation or surgery,