"Cancer" is when this system goes awry, and the cells in a tissue replicate faster than is healthy, and/or fail to die when they should.
Why does this happen? WE ALREADY KNOW WHY. We don't need billions more dollars to feed the Medical Sector.
Pollution and malnutrition are the two main causes of "cancer".
We can prevent and cure most cases of cancer with what we know right now, without any products or services of the Medical Biz (tradename: "healthcare").
A few examples:
Higher Vitamin D Intake Needed To Reduce Cancer Risk
Of course, the American Cancer Society opposes it:
New research shows vitamin D slashes risk of cancers by 77 percent; cancer industry refuses to support cancer prevention
The Vitamin C Foundation
Abram Hoffer via Doctor Youself
Speaking of low-carb
Is There a Role for Carbohydrate Restriction in the Treatment and Prevention of Cancer?
The Physicians Committee for Responsible Medicine
Mark Sisson of Mark's Daily Apple
"The researchers say fasting “flips a regenerative switch” that prompts stem cells to create white blood cells, essentially restoring the immune system."
Air Pollution's Impact on Cancer Is "Grossly Underestimated"
UPDATE March 5 2016
Five Important Facts About Cancer That Nobody Ever Talks About