A RANDOMIZED MULTICENTRE PHASE III STUDY FOR FIRST LINE TREATMENT OF YOUNG PATIENTS WITH HIGH RISK (AAIPI 2-3) DIFFUSE LARGE B-CELL LYMPHOMA (DLBCL): RITUXIMAB (R) PLUS DOSE-DENSE CHEMOTHERAPY CHOP14/MEGACHOP14 WITH OR WITHOUT INTENSIFIED HIGH-DOSE CHEMOTHERAPY (HDC) AND AUTOLOGOUS STEM CELL TRANSPLANTATION (ASCT). RESULTS OF DLCL04 TRIAL OF ITALIAN LYMPHOMA FOUNDATION (FIL)