Is a Duplication of 14q32 a New Recurrent Chromosomal Alteration in B-Cell Non-Hodgkin Lymphoma?

Identification of clonal chromosomal abnormalities involving 14q32 and its association with specific histological subtypes of non-Hodgkin lymphoma (NHL) has provided substantial insight to the genetic events leading to the disease. However, in some cases with inferior morphology of tumor cell chromosomes, the additional segment on chromosome 14 remains unidentified by cytogenetic banding techniques alone. To elucidate the origin of the additional chromosomal segment and to correlate the newly determined alterations with histology, metaphases from 15 NHL patients with add(14)(q32) were examined using fluorescence in situ hybridization (FISH) techniques after cytogenetic analysis had been performed. We found the duplication of 14q involving the q32 region in 6 cases with a dup(14)(q32) in 4 cases and a dup(14)(q24q32) in 2 cases. In 8 cases, FISH unveiled known NHL associated translocations; a t(14;18)(q32;q21) in 4 cases, a t(11;14)(q13;q32) in 2 cases, a t(8;14)(q24;q32) and a t(9;14)(p13;q32) in 1 case each. We also noted a t(14;17)(q32;q21) in 1 case. The use of FISH was a valuable asset in determining the origin of the additional material on chromosome 14q32, and helped resolve a group of B-cell NHLs with involvement of a duplicated 14q32 region.