We applied more sensitive immunohistochemical method, i.e. multilayered PAP, to investigate the expression and distribution of apoptosis-antagonizing gene bcl-2 in Hodgkin's disease (HD), bcl-2-positive Reed-Sternberg (RS) cells were found in 7 of 21 (33%) of HD, and 2 of 7 (mixed cellularity) accompanied by a lot of reactive lymphoid follicles, the germinal centers of which were also positive for bcl-2. In contrast, in 4 cases of inflammatory lymphoid follicular hyperplasia as positive controls, the mantle zones rich in long-lived B cells were strongly positive stained with bcl-2 antibody, whereas germinal centers were negative. Thus, our data indicate that overexpressed bcl-2 gene-mediated apoptosis impairment is strongly associated with pathogenesis of HD.