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AIM: To analyze the characterization of T-cell receptor-γ (TCR-γ) gene rearrangement in the gastrointestinal lymphomas and evaluate the value of PCR-SSCP analysis in gastrointestinal lymphomas investigation.METHODS: TCR-γgene rearrangement segments of gastrointestinal lymphomas were cloned and sequenced.Single clone plasmid and mixed clone plsamids were subsequently submitted to PCR-SSCP analysis to investigate the relationship between the number of amplified clones and band patts of the amplified products. The PCR products of TCR-γgene 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-γ 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 patt included 13 monoallelic gene rearrangements and 3 biallelic or oligoclonal gene rearrangements.CONCLUSION: The patt of TCR-γ, gene rearrangement in gastrointestinal lymphomas are similar to that of the nodular lymphomas. PCR-SSCP analysis for TCR-γ gene rearrangement can be applied both for adjuvant diagnosis of gastrointestinal lymphomas and analysis of the gene rearrangement patt. The ratio of TCR-γ gene rearrangements occurred in T-cell gastrointestinal lymphomas is significantly higher than that in B-cell gastrointestinal lymphomas. The gene rearrangement patt involves monoallelic and biallelic (or oligoclonal) gene rearrangement.