World heavyweight champion Wladimir Klitschko will defend his four titles against cancer survivor Francesco Pianeta on May 4 in Mannheim, Germany, Klitschko's management has announced. The 36-year-old Klitschko will defend his IBF, IBO, Super WBA and WBO belts against the undefeated Pianeta, 28, who has 15 knock-outs and one draw in 28 wins despite having been diagnosed with testicular cancer in early 2010.