High-dose cytarabine does not overcome the adverse prognostic value of CDKN2A and TP53 deletions in mantle cell lymphoma.

We revisited the prognostic value of frequently detected somatic gene copy number alterations (CNAs) in mantle cell lymphoma (MCL) patients treated first line with immunochemotherapy and autologous stem cell transplantation (ASCT), with or without high-dose cytarabine, in the randomized European MCL Younger trial. DNA extracted from tumor material of 135 patients (median age, 56 years) was analyzed by multiplex ligation-dependent probe amplification and/or quantitative multiplex polymerase chain reaction of short fluorescent fragments. As expected, MYC (18%) was the more frequently gained, whereas RB1 (26%), ATM (25%), CDKN2A (p16) (25%), and TP53 (22%) were the more frequently deleted. Whether adjusted for MCL International Prognostic Index (MIPI) or not, deletions of RB1, CDKN2A, TP53, and CDKN1B were associated with shorter overall survival (OS), similarly in both treatment arms, whereas CNAs in MYC, ATM, CDK2, CDK4, and MDM2 had no prognostic value. Additive effects were seen for CDKN2A (hazard ratio, 2.3; P = .007, MIPI-adjusted) and TP53 deletions (hazard ratio, 2.4; P = .007), reflected in a dismal outcome with simultaneous deletions (median OS, 1.8 years) compared with single deletions (median OS, 4.3 and 5.1 years) or without these deletions (median OS, 7 years), again similarly in both treatment arms. The additive prognostic effects of CDKN2A and TP53 deletions were independent of the Ki-67 index. Despite immunochemotherapy, high-dose cytarabine, and ASCT, younger MCL patients with deletions of CDKN2A (p16) and TP53 show an unfavorable prognosis and are candidates for alternative therapeutic strategies. This trial was registered at www.clinicaltrials.gov as #NCT00209222.