The Incidence Of A Chromosomal Translocation ITK-SYK Of Peripheral T-cell Lymphoma

Objective: To investigate the incidence of a novel chromosomaltranslocation t(5;9)(q33;q22)ITK-SYK of peripheral T-cell lymphoma（PTCL）,and the expression of SYK protein in normal T cells,B cells andperipheral T cell lymphoma.Methods:498PTCLs cases were selected; these included185cases ofperipheral T-cell lymphomas, unspecified (PTCL-U),179cases of NK/T-celllymphoma (NK/TL),67cases of anaplastic large-cell lymphoma (ALCL),38cases of angioimmunoblastic T-cell lymphoma (AITL) and29cases ofenteropathy-associated T-cell lymphoma (EATL). Interphase fluorescence insitu hybridization (FISH) was used to detect ITK and SYK genes involvedchromosome translocation in all of the498PTCLs cases. The expression ofSYK protein was detected in424PTCLs cases by immunohistochemistry.20cases of normal lymph tissue (10cases of reactive hyperplasia of the tonsil and10cases of fetal thymus) were studied as normal control.Results: In the498cases, we found only1case (0.2%) of NK/TL showingITK gene involved chromosome translocation. No SYK gene involvedtranslocation was identified in all cases. FISH analyses revealed that8%(16/185)PTCLs-U,7%(14/179)NK/TLs,8%(6/67) ALCLs,13%(5/38) AITLs,10%(3/29)EATLs had3to4copies of ITK gene.9%(18/185) PTCLs-U,6%(11/179) NK/TLs,4%(3/67) ALCLs,13%(4/29)EATLs carried3to4copies of SYKgene. Most of the424PTCLs (405/424) and all of the10normal lymph tissuecases showed weak or moderate cytoplasmic expression of SYK protein.Conclusions: The ITK and SYK genes involved chromosometranslocations are rare. Three to four copies of ITK and SYK genes are commongenetic abnormalities in PTCLs.Multiple copies of ITK and SYK genes may berelated to the pathogenesis of PTCLs. SYK is weakly or moderately expressedin the cytoplasm of normal T cells, B cells and peripheral T cell lymphoma.