METHODS: Using a panel of antibodies to CD10, Bcl-6, MUM1 and CD138, consecutive cases of primary UAT DLBCL were stratified into subgroups of germinal centre B-cell-like (GCB) and non-GCB, phenotype profile patterns A, B and C, as proposed by Hans et al. and Chang et al., respectively. EBER in situ hybridisation technique was applied for the detection of EBV in the tumours.
RESULTS: In this series of 32 cases of UAT DLBCL, 34% (11/32) were GCB, and 66% (21/32) were non-GCB types; 59% (19/32) had combined patterns A and B, and 41% (13/32) had pattern C. Statistical analysis revealed no significant difference in the occurrence of these prognostic subgroups in the UAT when compared with series of de novo DLBCL from all sites. There was also no site difference in phenotype protein expressions, with the exception of MUM1. EBER in situ hybridisation stain demonstrated only one EBV infected case.
CONCLUSIONS: Prognostic subgroup distribution of UAT DLBCL is similar to de novo DLBCL from all sites, and EBV association is very infrequent.
METHODS: ALK gene rearrangement was detected by immunostaining of ALK protein and fluorescence in situ hybridisation (FISH) targeting at the 2p23 region.
RESULTS: The expression of ALK protein was detected in 24/34 (71%) of the cases, and it was significantly higher in childhood cases (100%) when compared to adult cases (47%). The analyses by FISH were consistent with the results from immunostaining of ALK protein, but the analyses were only successful in 15/34 (44%) cases. FISH analyses detected extra copies of ALK gene in three cases, including one case that expressed ALK protein and showed 2p23 rearrangement.
CONCLUSIONS: The current series revealed a high frequency of ALK gene rearrangement, especially in the children. Immunostaining of ALK protein is a reliable indication of ALK gene rearrangement, and is superior to FISH. However, FISH analysis is useful in detecting other genetic aberrations that are not related to ALK gene rearrangement.