Frequency of BCL2 and BCL6 translocations in follicular lymphoma: relation with histological and clinical features

Follicular lymphomas (FLs) usually carry BCL2 translocations although BCL6 translocations are also present. We explored relationships between translocations status and clinical or histological parameters at diagnosis in 182 patients stratified in four groups: BCL2-/BCL6-, BCL2+/BCL6-, BCL2-/BCL6+ and BCL2+/BCL6+. BCL2-/BCL6- and BCL2+/BCL6-. Double negative cases were ascribed to lower histological grades. In contrast, BCL2-/BCL6+ cases corresponded to higher grades. However, a majority of BCL2+/BCL6+ tumours were classified as lower grades. These results were reinforced by the finding that double positive patients had lower LDH levels and PS than those with solitary BCL6 rearrangements. Bone marrow involvement was more frequent in BCL2+/BCL6+ compared with BCL2-/BCL6+ tumours. Our data confirm the presence of a relationship between histological grade and translocation status, suggesting that FLs carrying BCL6 translocations probably constitute a special biological subtype. Clinical and histological differences between BCL2-/BCL6+ and BCL2+/BCL6+ tumours could reflect an interplay between both translocations.