Expression of T cell receptor alpha gene (TCRA) in human rhabdomyosarcoma and other musculo-skeletal sarcomas.

Expression of the T cell receptor (TCR) genes is not restricted to T lymphocytes. Human prostate and breast express a truncated TCR gamma transcript. In the mouse, TCR alpha (TCRA) and beta partial transcripts are expressed by mesenchymal cells and TCRA transcripts by epithelial cells of the kidney. We show now that TCRA constant region expression is common in normal and neoplastic human cells of mesenchymal and neuroectodermal origin. TCR transcripts are derived from an unrearranged TCRA locus. Moreover, rhabdomyosarcoma cells highly expressed a specific J49-C splicing product deriving from the assembly of J49 segment and constant region. TCRA ectopic transcripts/proteins negatively regulate rhabdomyosarcoma cell growth as suggested by TCRA gene expression downmodulation effects using a specific duplex small interfering RNA.