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

Extraskeletal Ewing's Sarcoma with CD7 Positivity and T-cell Receptor/Immunoglobulin Rearrangement Masquerading as T-lymphoblastic Lymphoma

Background: Extraskeletal Ewing's Sarcoma (EES) may harbor more than one tumor-specific genetic abnormality, leading to diagnostic difficulties. Case report: We report a nine-year-old boy with recurrent mass of his right thigh. Tumor cells were round, with scant cytoplasm, finely dispersed chromatin, and inapparent, small nucleoli. The initial misdiagnosis was T-lymphoblastic lymphoma due to CD7 and TCR/Ig monoclonal rearrangement. As it expressed NKX2.2 and harbored an EWSR1-FLI1 fusion transcript, the diagnosis was changed to EES. The child underwent EES therapy with good initial response, but had a subcutaneous relapse at 22 months. Conclusion: In addition to typical genetic alterations, Ewing sarcoma can also express CD7 and TCR/Ig rearrangement, which are not limited to lymphoma.

Molecular characterization of the feline T-cell receptor γ alternate reading frame protein (TARP) ortholog

T-cell receptor γ alternate reading frame protein (TARP) is expressed by human prostate epithelial, prostate cancer, and mammary cancer cells, but is not found in normal mammary tissue. To date, this protein has only been described in humans. Additionally, no animal model has been established to investigate the potential merits of TARP as tumor marker or a target for adoptive tumor immunotherapy. In this study conducted to characterize feline T-cell receptor γ sequences, constructs very similar to human TARP transcripts were obtained by RACE from the spleen and prostate gland of cats. Transcription of TARP in normal, hyperplastic, and neoplastic feline mammary tissues was evaluated by conventional RT-PCR. In felines similarly to the situation reported in humans, a C-region encoding two open reading frames is spliced to a J-region gene. In contrast to humans, the feline J-region gene was found to be a pseudogene containing a deletion within its recombination signal sequence. Our findings demonstrated that the feline TARP ortholog is transcribed in the prostate gland and mammary tumors but not normal mammary tissues as is the case with human TARP.