The role of translocations involving c-MYC/8q24, BCL2/18q21 and/or BCL6/3q27 genes in patients with follicular lymphoma. Retrospective analysis of single-centre data

Aim of the issue was to compare clinical characteristics and treatment results of patients with follicular lymphoma (FL) with translocations involving loci of c-MYC/8q24, BCL2/18q21 and/or BCL6/3q27 genes and patients with high - grade B-cell lymphoma [High - grade B-cell lymphoma (HGBL), double - hit (DH)]. Materials and methods. Since 2004 to 2017 years in National Research Center for Hematology 12 patients with high - grade B-cell lymphoma double - hit (HGBL DH) and 6 FL patients with translocations involving c-MYC and BCL2 and/or BCL6 had been treated. We performed a comparative analysis of clinical characterisctics in both groups. As primary endpoints was assessed frequency of complete remission (CR) or progressive disease (PD); as secondary endpoints - overall (OS) and event - free survival (EFS). Results. 5 patients with HGBL DH had c-MYC/BCL6, 7 - c-MYC/BCL2 rearrangements; 2 patients with FL had c-MYC/BCL2, 3 - c-MYC/BCL6, 1 - c-MYC/BCL2/BCL6 rearrangements. FL was represented by grade 3A in 2, grade 3B - in 4 cases, 3 of them had large - cell transformation. In HGBL DH and FL patients had no significant differences in clinical characteristics. The majority of patients had a widespread tumour, increased LDH activity, high frequency of extranodal and bone marrow involvement. Ki-67 expression level was lower in patients with FL (p<0.05). Patients with HGBL DH were treated with R-BL-M-04, R-(DA)-EPOCH, CHOP-21±R, with FL - R-CHOP-21 or R-(DA)-EPOCH. Frequency of CR in HGBL DH and FL was 42% and 33%, respectively. Frequency of PD was 50% in both groups. Two - year OS of patients with HGBL DH and FL harbouring c-MYC, BCL2 and/or BCL6 rearrangements was 50% and 42% respectively, p=0.85. Two - year EFS was 33% in both groups, p=0.8. Conclusions. We presented highly aggressive variant of FL grade 3 harbouring c-MYC, BCL2 and/or BCL6 rearrangements that had similarly poor prognosis as patients with HGBL DH.