Cancer is a malignant tumor. One that invades other tissues. It only takes one cell lodging somewhere to start a new cancer. Once it gets in the blood stream it spreads to other areas.
Cancer can strike anyone.
Example of grandparents dying 4 months apart. Anything that mutates the cell. Many things can cause cancer but some are more likely than others. The object is to play the odds and increase your chance of living. This is similar to lifestyle SDA teach.