the cancer information service is the national cancer institute's link to the public, interpreting and explaining research findings in a clear and understandable manner, and providing personalized responses to specific questions about cancer. access the cis by calling 1-800-4-cancer (1-800-422-6237), or by using the livehelp instant-messaging service at https://cissecure.nci.nih.gov/livehelp/welcome.asp. also called cis.