Morphologic pattern of CD30 distribution within neoplastic cells in Hodgkin lymphoma.

Abstract

e19535 Background: CD30 protein is expressed on Hodgkin and Reed-Sternberg (HRS) cells in nearly all cases of classical Hodgkin lymphoma (HL). CD30 is present on a cell membrane and on the Golgi complex of the endomembrane cell system. Given the growing clinical application of CD30 targeting we were interested to see if there is variability in distribution of CD30 protein between the cell surface and the cytoplasm. External exposure of CD30 is most likely a critical condition of successful interaction with the ligand and possibly, a predictive factor for response to CD30 antibody. To our knowledge, clinical data on CD30 expression have not yet been published in the context of cell topography. Methods: The CD30 protein was evaluated in formalin-fixed paraffin-embedded (FFPE) tissue sections by immunohistochemistry (IHC) with monoclonal mouse anti-human antibody CD30 (clone Ber-H2) (Dako). IHC was performed using the EnVision Plus Detection Systems LSAB kit (Dako Corp., Carpinteria, CA), and an antigen-retrieval technique was applied. Morphological pattern (localization of CD30) of CD30 expression was evaluated in each case under a microscope examination. Results: FFPE tissue specimens from 83 newly diagnosed and relapsed (n=78 and n=5, respectively) HL patients were examined. The average (range) of patient age was 39 (18-89), male/female ratio was 1/0.88. Histological subtypes of HL were nodular sclerosis in 87%, mixed cellularity in 8%, lymphocyte rich in 3% of cases, and 1 case of lymphocyte-depleted classical HL. Immunophenotype was typical of classical HL, and HRS cells were positive for CD30 in all cases. Immunostaining for CD30 was present on the Golgi body in 98% of cases, and it was demonstrated on the cell membrane in 27% of cases. Conclusions: In our series of 83 patients with classical HL, predominant pattern of CD30 expression was cytoplasmic (Golgi body), and only 27% of cases demonstrated cell surface expression. We hypothesize that cell surface expression of CD30 protein might predict a response to anti-CD30 antibody that is in the order of magnitude of 30% complete remissions in recurrent HL.