Germany's Harald zur Hausen and French researchers Francoise Barre-Sinoussi and Luc Montagnier shared the 2008 Nobel Prize in medicine Monday for discovering the AIDS virus and the role of viruses in cervical cancer. Barre-Sinoussi and Montagnier were cited for their discovery of human immunodeficiency virus, or HIV; zur Hausen was cited for finding human papilloma viruses that cause cervical cancer, the second most common cancer among women.