Andrew McMahon Born September 3 1982 Is A Maverick Recording Singer/songwriter And The Vocalist Pianist And Main Songwriter For The Band Jack's Mannequin And The Geffen/Drive-Thru Records Band Something Corporate. He Was Diagnosed With Leukemia On June 1st 2005. On August 23rd 2005 Andrew Received A Stem Cell Transplant The Donor Was His Sister Katie McMahon.