Marker Expression in Peripheral T-Cell Lymphoma Unspecified: Proposal of a Clinical-Pathologic Prognostic Score.

Peripheral T-cell lymphoma unspecified (PTCL/U) represents the commonest form of T-cell tumor in Western Countries according to the WHO Classification. So far, no concrete attempts have been made in order to apply a wide panel of markers to a large series of PTCLs and to assess the impact of phenotype on prognosis and survival. We then studied the protein expression and outcome of 148 PTCL/U cases, along with 45 tumors of the AILD type, utilizing highly standardized high-throughput technology.

Tissue micro-arrays corresponding to the above mentioned cases were constructed and analyzed with a panel of 18 commercially available markers. In 93 patients with PTCLs/U clinical data were available and were matched with the protein expression profile. Interestingly, most of these patients had been included in a previous study that proposed a prognostic index for PTCL/U (PIT) (

An aberrant phenotype with frequent loss of CD5 and/or CD7 was typical for all PTCLs, irrespectively of the subtype (unspecified or AILD-type). CD20 and CD15 were rarely aberrantly expressed, at times simultaneously with CD30. EBER positivity and CD15 expression emerged as adverse prognostic factors, while CD56 and CD57 were unremarkable. Among PTCLs/U, the proliferation-associated protein Ki-67 was found to be prognostically relevant and was then integrated in a new prognostic score, including age (>60 years), high serum lactate dehydrogenase, poor performance status, and Ki-67 ³ 80%. Such score was associated with the overall survival (p<0.0001) and was more a powerful predictor than PIT that - however - maintained its relevance.

Our retrospective analysis shows a wide range of protein expression in PTCLs and candidates a new prognostic index. The latter represents one of the first examples of mixed score (including patient- and tumor-specific factors) applied to malignant lymphomas and may be the basis for future prospective therapeutic trials.