CD30 is a transmembrane receptor with restricted expression on activated T and B cells in normal lymphoid tissues.1,2 In neoplastic conditions, strong CD30 expression is a feature of classical Hodgkin lymphoma and anaplastic large cell lymphomas (ALCL). Given the high response rates seen in phase 2 studies, the novel CD30+ tumor-targeting antibody drug–conjugated brentuximab vedotin (BV) was approved treating relapsed or refractory CD30+ HL and systemic ALCL.
PTCLs compose a group of aggressive neoplasms characterized by unsatisfactory response to multiagent chemotherapy. Recent reports document promising efficacy of BV in nonanaplastic CD30+ PTCLs5,6; however, CD30 protein expression in PTCLs is highly heterogeneous among entities,7-16 and the reliability of CD30 status determined by immunohistochemistry (IHC) in the context of prospective BV therapy remains a critical open question. This prompted us to investigate the correlation between CD30 protein expression as evaluated by IHC and messenger RNA (mRNA) expression in a large series of PTCLs to assess if the immunohistochemical scores sufficiently capture variations seen at the mRNA level. We show a consistently significant correlation between mRNA and protein expression for different PTCL entities, supporting that, in clinical practice, IHC is a valuable tool for determining CD30 status in PTCLs.