Celebs Tweet For World Cancer Day

World Cancer Day, February 4, 2012, is officially here. And as a global advocacy day, people and organizations are getting involved all over the world -- including celebrities. Those taking a stand include Ethan Zohn, who announced last November that his Hodgkin's Lymphoma had returned, and Katie Couric, who lost her husband Jay Monahan to Colon Cancer in 1998.

Couric and Zohn are among a collection of other celebrities tweeting their support for #WorldCancerDay. Click here for ways you can get involved to take a stand against cancer today.