Ki-1 (
CD30) antigen expression has been considered to be restricted to hematopoietic tissues including the recently described
anaplastic large cell lymphoma and Reed-Sternberg (RS) cells in
Hodgkin's disease. Its presence on some activated lymphocytes in non-neoplastic lymphoid tissues has been used as evidence that such cells might represent the physiologic counterpart of RS cells. In this study expression of
CD30 antigen in 117 nonhematopoietic
tumors was investigated using
monoclonal antibody Ber-H2. The
antigen was regularly expressed in frozen section (strongly) and
paraffin section (less strongly) by
embryonal carcinomas (8 of 10 studied) and the embryonal elements of mixed
germ cell tumors (4 of 4), but not in other types of
germ cell tumors (0 of 11) or nonhematopoietic
tumors (0 of 92). Normal adult, neonatal, and fetal testes were negative for
CD30 antigen, as were other fetal tissues and placenta. Ki-1 antibody gives similar results in frozen section. These findings have implications for theories suggesting an origin of RS cells from activated lymphocytes. They are also important for determining the diagnostic significance of CD30 positivity in a
tumor of unknown origin, and suggest possible new uses for CD30
antibodies in routine diagnostic immunohistology.