LEXINGTON, Mass., June 18, 2012 (GLOBE NEWSWIRE) -- Agenus, Inc. (Nasdaq:AGEN), a biotechnology company working to develop treatments for cancers and infectious diseases, today announced that it is set to join the broad-market Russell 3000® Index, Russell Global Index, and Russell Microcap® Index when Russell Investments reconstitutes its comprehensive set of U.S. and global equity indexes on June 25, according to a preliminary list of additions on www.russell.com.