Gene expression analysis of peripheral T-cell lymphoma not otherwise specified reveals two distinct subgroups and recurrent PDGFR-alpha deregulation

Peripheral T-cell lymphomas (PTCLs) represent approximately 12% of lymphoid neoplasms.Their incidence varies in different countries and races, being higher in HTLV-1 endemic areas (Asia, Caribbean basin and some parts of the United States).PTCLs are a heterogeneous group of tumours that in the REAL/WHO Classification are roughly subdivided into specified and unspecified (or not otherwise specified, NOS) forms. In particular, the latter – corresponding to about 50% of T-cell lymphomas – cannot be further classified on the basis of morphology, phenotype and conventional molecular studies. Immunohistochemistry does generally show T-cell associated molecule expression, although the phenotypic profile is aberrant in about 80% of cases, CD5 and CD7 being the most frequently defective antigens.