DETECTION OF CLONAL T-CELL POPULATIONS IN GASTROINTESTINAL LYMPHOMAS BY ANALYSIS OF CRNA CONFORMATIONAL POLYMORPHISMS OF REARRANGED T-CELL-RECEPTOR-GAMMA GENES

Analysis of complementary RNA molecules of junctional regions of rearr anged T-cell-receptor-gamma genes show a pattern of conformational pol ymorphisms which is specific for an individual lymphocytic clone. In a blinded study we analysed formalin-fixed, paraffin-embedded histologi cal specimens from gastrointestinal lymphomas and control tissues (lym phomas: pleomorphic T-cell 10, anaplastic large cell [Ki1+] 9, centrob lastic 5, immunocytoma 1, B-CLL 2, Hodgkin's 2, centroblastic-centrocy tic 1, MALT [mucosa associated lymphoid tissue] 1,T-cell acute lymphob lastic leukaemia 1, non-lymphoid or polyclonal lymphoid tissues 5). Ju nctional regions of rearranged TCR-gamma genes were amplified by the p olymerase chain reaction and the products were transcribed into cRNA. Conformational patterns of cRNA molecules were analysed by polyacrylam ide gel electrophoresis. 13/20 T-lineage lymphomas and the T-cell acut e lymphocytic leukaemia displayed a distinct cRNA band pattern, all B- lineage lymphomas and the nonlymphoid control tissues were negative. O nly one case of nasopharyngeal (lymphoepithelial, Schmincke-Regaud) ca rcinoma showed a faint cRNA banding pattern. This novel and non-radioa ctive assay allows for the rapid detection and molecular characterizat ion of clonal lymphoid populations in minute histological biopsy speci mens.