because, usually it is a defect in a tumor suppressing gene such as p53.
No
Cancers are tumers that start in your body and lead i to the blood stream causing disfunctions. It develops over time. Genetic disorders come from your genes. Its passed down through generations....
Down Syndrome,Huntington's Disease,Sickle Cell,Hemophelia, and many others
There is some evidence that some forms of cancer may be.