Skip to main content

An official website of the United States government

Search

About Cancer
Cancer Types
Research
Grants & Training
News & Events
About NCI

Home
About Cancer
Understanding Cancer
What Is Cancer?
Defining Cancer

Understanding Cancer

Defining Cancer

A simple explanation of what cancer is and how it can spread through the body.

Posted: April 28, 2023

About

About This Website
en Español
Reuse & Copyright
Social Media

Resources

Contact Us
Publications
Dictionary of Cancer Terms
Find a Clinical Trial

Policies

Accessibility
FOIA
Privacy & Security
Disclaimers
Vulnerability Disclosure

Sign up for email updates

Enter your email address

National Cancer Institute at the National Institutes of Health

Contact Us

Live Chat

1-800-4-CANCER

NCIinfo@nih.gov

Site Feedback

Follow us

U.S. Department of Health and Human Services National Institutes of Health National Cancer Institute USA.gov