National Cancer Institute at the National Institutes of Health
Cancer.gov: Cancer Causes and Risk Factors
This site provides links to articles that deal specifically with many different causes of cancer, such as genetic, hormonal, or from a chemical that is inhaled or eaten.
Other
Cancer Index: Index Home
This site from the Cancer Index provides a long list of links to sites on every imaginable type of cancer, genes related to cancer, treatments, and resources for cancer patients and their families. The index can be viewed alphabetically,...