Immunohistochemistry as a valuable tool to assess CD30 expression in peripheral T-cell lymphomas: High correlation with mRNA levels

Abstract

The extended use of brentuximab-vedotin was reported for CD30+ nonanaplastic peripheralT-celllymphomas(PTCLs)with promising efficacy. CD30 status assessmentis thus a critical factor for therapeutic decision, but the reliability of immunohistochemistry (IHC) in evaluating its expression remains to be defined. This prompted us to investigate the correlation between semiquantitative CD30 protein assessment by IHC andmessengerRNA(mRNA) assessment by micro arraysinacohortof376 noncutaneous PTCLs representative of the main entities. By IHC, CD30 expression was heterogeneous across and within entities and significantly associated with large tumor cell size. In additionto100% anaplastic large-cell lymphomas, 57%ofother PTCL entities were CD30-positive at a 5% threshold. CD30 protein expression was highly correlated to mRNA levels. mRNA levels were bimodal, separating high from low CD30-expressing PTCL cases. Weconclude that IHC is a valuable tool in clinical practice to assess CD30 expression in PTCLs.