Abstract
The purpose of this work was to study retrospectively the molecular response and outcome of 19 gastric mucosa associated lymphoid tissue (MALT) lymphoma patients achieving histological remission after chemotherapy or surgery. Immunoglobulin heavy chain variable (IgVH) gene rearrangements were studied by PCR in biopsies obtained at diagnosis and follow-up. Presence of t(11;18)(q21;q21) was studied by FISH or RT-PCR. Sequencing analysis of three t(11;18)(q21;q21) positive and two negative lymphomas with persistent monoclonal IgVH rearrangements was also performed. Long-term IgVH monoclonality was demonstrated in 11/19 patients (58%); in five of them monoclonal rearrangements were present in all samples throughout the follow-up. Persistent IgVH monoclonality was detected a median of 49 months after the achievement of histological response and did not condition histological relapse in most cases. All three t(11;18)(q21;q21) positive patients had maintained IgVH monoclonality and sequencing analyses revealed the same mutated IgVH alleles in the diagnostic and the follow-up samples. Over half of the patients with gastric MALT lymphoma with histological response after chemotherapy and/or surgery have long-term persistent monoclonality. The presence of t(11;18)(q21;q21) seems to condition long-term persistence of the initial lymphoma clone.™
Notes
This study has been presented at the 49th Annual Meeting of the American Society of Hematology 2007.