Aberrant cytoplasmic expression of proliferating cell nuclear antigen in Hodgkin's disease

During a study using a monoclonal antibody directed against proliferating cell nuclear antigen (PCNA) to assess the proliferative activity of tumors, it was noted that the cytoplasm of Reed-Sternberg (RS) cells and variants of these cells in cases of Hodgkin's disease reacted very positively. This aberrant expression of PCNA has not been observed in any other tumor or in cells from normal tissues. The biological significance of this observation is currently unknown, but it may have diagnostic utility in detecting and identifying RS cells.