Cancer cells have characteristics that can be associated with their ability to grow uncontrollably. 444
22.2 Origin of Cancer
Mutations of proto-oncogenes and tumor-suppressor genes are linked to the development of cancer. 446
22.3 Causes of Cancer
A number of agents are known to bring about the mutations that cause cancer, and a mutated gene can be inherited. 448Environmental factors play a role in the development of cancer. 448
22.4 Diagnosis and Treatment
There are few routine screening tests for specific cancers, and cancer often goes undetected until it is advanced. New ways to diagnose cancer are under investigation. 450Surgery, radiation, and chemotherapy are presently the standard ways of treating cancers. 452Molecular knowledge of cancer has produced many specific types of drugs and therapies that are now in clinical trials. 454It is possible to take protective steps to reduce the risk of cancer. 456