Frequent chromosome arm 13q deletion in aggressive non-Hodgkin's lymphoma

To clarify the role of allelic loss on chromosome arm 13q in lymphomagenesis, we performed fluorescence in situ hybridization (FISH) analysis of a total of 43 primary lymphomas, including both indolent and aggressive non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD), using the specific probes at RB1 and D13S319 loci on the centromeric portion of chromosome arm 13q. Monosomy at either or both RB1 and D13S319 loci was detected in 15 of 43 (35%) lymphomas (14 of 43 cases at RB1 locus and seven of 43 cases at D13S319 locus); the 13q deletion was frequently detected in the aggressive NHLs (40%; 12 of 30 cases) compared with that in indolent NHL (17%; one of six cases) and a subset of HD (29%; two of seven cases). There are only six cases of 43 which have total monosomy 13q14, all aggressive NHL, 14% of total or 20% of this subgroup. In addition, we analyzed the loss of heterozygosity in 15 of the 43 primary lymphoma samples for several polymorphic microsatellite loci (D13S168, RB1 and D13S272) on the chromosome arm 13q, and confirmed the 13q deletion in four of five cases that were positive on FISH analysis. The subchromosomal region frequently altered in lymphoma on 13q14 is the region around RB1 locus and centromeric to D13S319 locus, which is an overlapped region frequently deleted in chronic lymphocytic leukemia. Together, our data indicate that the 13q alterations are present in a variety of types of lymphoma and occur in a significant proportion of aggressive NHLs, suggesting the possible presence of common candidate gene(s) on the 13q14 region, whose alteration may play an important role in the formation or development of a wide variety of mature lymphoid malignancies.