The contribution of molecular biology in the diagnosis of human lymphomas

The relationship between T cell receptor (TCR) beta and gene immunoglobulin heavy chain locus was investigated in 25 cases of unselected human lymphomas as well as in normal and non-neoplastic lymphoid tissues. Hybridizing our blots with Jurkat 2, a clone specific for the beta chain gene of TCR, did not demonstrate extra bands in non-neoplastic tissues composed of 50-95% T-cells. On the contrary, rearranged bands were detected in six out of six cases of T-cell lymphomas. No TCR beta gene rearrangements were detected in 11 B-cell lymphomas, which in turn presented modification of the immunoglobulin heavy chain gene germline configuration. Our results suggest that TCR beta chain gene rearrangements are a good marker for human T-cell neoplasias in humans and complement the analysis with immunoglobulin genes probes. Eighth samples were devoid of any rearrangements: this group comprises cases of Hodgkin's disease T-lymphoblastic lymphomas in clinical remission and malignancies of unknown origin, as discussed in the text. We conclude that the analysis using DNA probes specific for TCR beta and IgH genes can be of aid to the pathologist in the diagnosis and classification of human lymphomas.