Immunohistochemical study on the distribution of α and β subunits of S-100 protein in human neoplasm and normal tissues

Abstract

The immunohistochemical distribution and localization of the α and β subunits of S-100 protein in human neoplasms and normal tissues were studied by the PAP method using monospecific rabbit antibodies against each subunit, β subunit immunoreactivity was detected in all S-100-positive cells and tumors reported previously. In contrast a subunit immunoreactivity was absent from Schwann cells, schwannomas, neurofibromas, granular cell myoblastomas, pituicytes of the neurohypophysis, Langerhans cells, interdigitating reticulum cells, and histiocytosis X cells. Interestingly, only the α subunit was detected in neurons of both central and peripheral nervous system, and in lymph node macrophages. Human S-100-positive cells are divided into three groups; the first is composed of cells containing only the β subunit (probably S-100 b; ββ), the second consists of cells containing both the a and β subunits, and the third is composed of cells containing only the α subunit (probably S-100ao; αα). The ontogentic relationships between S-100-positive cells and tumors are discussed in the light of these findings.