Detection of p53 in Hodgkin's disease using the monoclonal antibody PAb248

The recent demonstration that the murine anti-p53 monoclonal antibody PAb248 can identify human p53 in a variety of normal tissues proves that immunohistochemical detection does not necessarily indicate the presence of mutations. PAb248 can detect p53 protein in a cytoplasmic-perinuclear localization, not previously described. The present study presents the expression of this antibody in a series of 34 cases of Hodgkin's disease, comparing it with the antibodies CM1, PAb1801, and PAb240. In all cases, PAb248 showed uniform cytoplasmic-perinuclear staining in small and medium-sized lymphocytes, while it was constantly negative in Hodgkin, Reed-Sternberg (R-S/H) cells, and variants. This pattern of staining was the opposite to that observed with the antibodies CM1, PAb1801, and PAb240, where the staining was nuclear and restricted to the R-S/H cells, with the small lymphocytes being negative. p53 can be found in different conformations and localizations, with the cytoplasmic-perinuclear localization mainly, although not exclusively, being found in normal and reactive tissues and the nuclear localization being mainly expressed by neoplastic cells. These results give further support to the theory that the R-S/H cells are the neoplastic population in Hodgkin's disease, while the surrounding lymphocytes are reactive.