This work has been financially supported by Fundación ASTURCOR (to S.R.R); the FIS/FEDER (PI11/01728 to A.F.F. and PI11/02795 to E.D.-A.); the ISCIII (CP11/00131 to A.F.F.); the FIS PI11/01359 to M.R.; the Spanish Ministry of Health (PS09/02454 and PI12/01080 to M.F.F.); the Spanish National Research Council (CSIC; 200820I172 to M.F.F.); Instituto Universitario de Oncología del Principado de Asturias (to C.F. and G.F.B.); Ramon Areces Foundation (to M.F.F. and G.F.B.); Fundacion Cientifica de la AECC (to R.G.U.); RD12/0036/0013, BFU-2010-16025, RD12/0036/0030 (to P.S.), RD12/0036/0015 and PI11/00929 (to C.S.), and S2011/BMD-2328 TIRONET (to P.S. and M.R.). Tumor samples were obtained with the support of Red de Biobancos ISCIII (RD09/0076/0059). V.M. is supported by a fellowship of “la Caixa”/Spanish National Cancer Research Center international PhD Program. The IUOPA is supported by the Obra Social Cajastur, Spain.