ANALYSIS OF 14Q-HODGKINS-LYMPHOMAS BY FLUORESCENCE IN-SITU HYBRIDIZATION( DERIVATIVE CHROMOSOMES IN NON)

The most common chromosomal abnormality observed in non-Hodgkin's lymp homas (NHL) involves the structural alteration of the q arm of chromos ome 14. It is not always possible, however, to fully analyse such deri vative chromosomes by Giemsa-banding. Therefore, we have applied the f luorescence in-situ hybridization (FISH) technique of chromosome paint ing to elucidate the origins of the der(l4) chromosomes in 8 cases of NHL. In 2 NHL the der(l4) appeared to be the product of the t(14;18)(q 32;q21) translocation, but were not accompanied by the reciprocal der( 18) chromosome. In 3 cases the breakpoint was at 14q32 but the translo cated material appeared not to be from chromosome 18 and in 2 cases th e breakpoint was centromeric to 14q32. One case with a t(14;18)(q32;q2 1) was also analysed as a control. Dual painting was carried out with paints for chromosome 14 and either chromosome 3, 8, 10, 11, 18 or 19. In the control and 2 other cases the translocated material was demons trated to be from chromosome 18, in two cases it was from chromosome 3 and in 1 case there was an unusual insertion of chromosome 11 materia l. We were unable to identify the origins of the translocated material in 1 NHL and in the final case the apparent der(l4) was demonstrated not to contain chromosome 14 material. These data demonstrated the uti lity of the FISH technique for analysing malignant cell karyotypes, an d in particular indicated the potential of this approach for identifyi ng cases containing putative NHL associated oncogenes that may have be en translocated adjacent to the immunoglobulin locus at 14q32.