BCL6gene amplification/3q27 gain is associated with unique clinicopathological characteristics among follicular lymphoma without BCL2gene translocation

Although approximately 10–20% cases of follicular lymphoma lack BCL2gene rearrangement, there are few reports having described the alternative genetic aberrations and their association about clinicopathological features. In this study, analysis by Fluorescence in situhybridization of BCL6gene aberrations in 100 follicular lymphoma cases without IGH/BCL2rearrangement resulted in the identification of four subgroups. Group I: BCL6gene rearrangement (n=41); Group II: BCL6gene amplification/3q27 gain (n=30); Group III: the absence of both (n=23); and Group IV: the presence of both (n=6). Group II showed higher grade morphology (Grade 3a/b: 93%), higher bcl2 and MUM1 expression (73 and 57%, respectively), and more frequent combination with BCL2gene amplification/18q21 gain (90%) than the other groups. BCL6gene aberration, especially amplification/3q27 gain, indicates the presence of certain morphological and phenotypical findings in follicular lymphoma cases without IGH/BCL2rearrangement.