Personalized medicine in lymphoma: is it worthwhile? The mantle cell lymphoma experience.

706 haematologica | 2015; 100(6) The 2008 WHO classification described 36 different types of mature B-cell neoplasms, encompassing provisional entities and subtypes. Histological and molecular findings, as well as profound differences in clinical behavior, warrant such a detailed classification. Moreover, even within single lymphoma entities a considerable heterogeneity in disease presentation and outcome among different patients is regularly observed. Hence, a more comprehensive characterization of the patient as well as disease becomes crucial to tailor a “personalized” approach based on the specific features of each of our patients. An illustrative example is mantle cell lymphoma (MCL). MCL was first recognized as a separate entity as “centrocytic type” in the Kiel classification and subsequently renamed “mantle cell lymphoma”, but was generally not accepted before the 1994 REAL classification. With a 36month median overall survival (OS) it was the lymphoma subtype with the worst long-term prognosis, lacking both the prolonged survival of the indolent lymphomas and the curative potential of the aggressive ones. Since then, substantial progress has been made based on an improved diagnostic accuracy by the detection of the chromosomal translocation t(11;14) and the resulting cyclin D1 overexpression. Accordingly, its prognosis, formerly recognized as uniformly dismal, has nowadays changed into a spectrum of highly heterogeneous clinical scenarios, irrespective of patient age at presentation. Reviewing our daily experience, there are certainly young MCL patients who initially respond to cytarabinecontaining regimens followed by autologous stem-cell transplantation (ASCT), but who rapidly progress with chemorefractory disease shortly after. On the other hand, some young MCL patients are alive without evidence of lymphoma ten years after ASCT. Similarly, we recollect elderly patients responding to conventional immunochemotherapy and relapsing six months after end of rituximab maintenance. Other individuals may present with a long history of indolent MCL, yet finally, after years of ‘watch and wait’, transform into highly aggressive disease, Personalized medicine in lymphoma: is it worthwhile? The mantle cell lymphoma experience