DETECTION OF BCL2 REARRANGEMENT IN ARCHIVAL CYTOLOGICAL SMEARS OF B-CELL LYMPHOMAS

The application of polymerase chain reaction (PCR) to cytological mate rial represents a promising, relatively noninvasive approach to clinic al molecular genetic analysis. The detection rate of the t(14;18), the most common translocation in B-cell lymphomas, which results in rearr angement of the immunoglobulin heavy chain (IGH) and BCL2 genes, has n ot been examined in archival cytological smears. We studied 10 cases o f lymphoma that showed a cytogenetic t(14;18) in a surgical specimen a nd for which were available both lymphoma DNA from the same specimen a nd prior or subsequent archival cytological smears, either FNA or exfo liative, diagnosed as positive for lymphoma. The paired DNA samples, r espectively extracted from the archival smears and frozen surgical bio psy tissue, representing clinical intervals of up to 20 mo, were studi ed in each case by PCR with IGH and BCL2 major breakpoint region prime rs. In four cases, the same clonotypical PCR product was seen in both samples. In four other cases, neither sample yielded a PCR product-the se cases were also negative by Southern blotting using a BCL2 major br eakpoint region probe. In one case, the PCR product could only be demo nstrated in DNA from frozen tissue. Finally, in one other case, a PCR product was only detected in DNA from archival cytological smears. Thu s, the overall concordance of PCR results in the paired DNA samples wa s 80%. Our findings suggest that, in cases of B-cell lymphoma previous ly characterized by PCR, the t(14;18) can be detected in archival cyto logical smears in the majority of cases, thereby providing valuable da ta regarding the clonal derivation of metachronous lymphoma samples in which only cytological material is obtained.