[Clonal relationship between transformed and non-transformed components in mucosa-associated lymphoid tissue lymphoma].

OBJECTIVE

To analyze the clonal relationship between transformed and non-transformed components in mucosa-associated lymphoid tissue (MALT) lymphoma.

METHODS

Six cases of MALT lymphoma with high-grade transformation were studied. Immunohistochemical study was carried out by EliVision using bcl-10 antibody. Reverse transcription-polymerase chain reaction was used to detect the presence of API2-MALT1 fusion gene transcripts. The target cells were selected by laser microdissection and studied by polymerase chain reaction and sequence analysis for rearrangement of immunoglobulin heavy chain gene.

RESULTS

In the 6 cases of MALT lymphoma with high-grade transformation, nuclear and cytoplasmic expression of bcl-10 was demonstrated in 1 case, while API2-MALT1 fusion gene was present in 2 cases. Identical fragments of rearranged immunoglobulin heavy chain gene were detected in both transformed and non-transformed components in each of the 6 cases, except for the differences at 2 nucleotide positions in N or D regions in 2 cases.

CONCLUSION

The tumor cells from both transformed and non-transformed components in MALT lymphoma derive from the same clone.