Investigation of T-cell receptor-gamma gene rearrangement in gastrointestinal lymphomas by PCR-SSCP analysis.

AIM

To analyze the characterization of T-cell receptor-gamma (TCR-gamma) gene rearrangement in the gastrointestinal lymphomas and evaluate the value of PCR-SSCP analysis in gastrointestinal lymphomas investigation.

METHODS

TCR-gamma gene rearrangement segments of gastrointestinal lymphomas were cloned and sequenced. Single clone plasmid and mixed clone plasmids were subsequently submitted to PCR-SSCP analysis to investigate the relationship between the number of amplified clones and band patterns of the amplified products. The PCR products of TCR-gamma gene rearrangement of 40 gastrointestinal lymphomas were electrophoresed on agarose gels and the positive cases on agarose gels were studied by SSCP analysis.

RESULTS

The sequencing showed that TCR-gamma gene rearrangement of the gastrointestinal lymphomas included functional gene and pseudogene with extensive variety in the junctional regions. In SSCP analysis, the number of the single-stranded bands was about two times of the number of amplified clones, and double-stranded band became broad with the increased number of the amplified clones. Thirteen of the 25 B-cell gastrointestinal lymphomas and 14 of the 15 gastrointestinal T-cell lymphomas were positive detected on agarose gel electrophoresis. Of the positive cases detected by SSCP analysis, 3 B-cell lymphomas and 13 T-cell lymphomas showed positive bands. The other cases showed only smears. The rearranged pattern included 13 monoallelic gene rearrangements and 3 biallelic or oligoclonal gene rearrangements.

CONCLUSION

The pattern of TCR-gamma gene rearrangement in gastrointestinal lymphomas are similar to that of the nodular lymphomas. PCR-SSCP analysis for TCR-gamma gene rearrangement can be applied both for adjuvant diagnosis of gastrointestinal lymphomas and analysis of the gene rearrangement pattern. The ratio of TCR-gamma gene rearrangements occurred in T-cell gastrointestinal lymphomas is significantly higher than that in B-cell gastrointestinal lymphomas. The gene rearrangement pattern involves monoallelic and biallelic (or oligoclonal) gene rearrangement.