IMMUNOHISTOCHEMICAL DETECTION OF S-100, S-100-ALPHA, S-100-BETA PROTEINS, GLIAL FIBRILLARY ACIDIC PROTEIN, AND NEURON-SPECIFIC ENOLASE IN THE PRENATAL AND ADULT HUMAN SALIVARY-GLANDS

Developing human fetal salivary glands of gestational age from 10 to 4 0 weeks (n=100) and normal adult glands (n=10) were examined for immun oreactivity to S-100 protein and its subunits S-100alpha, S-100beta, g lial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE ). In the early intermediate developmental stage (19-32 weeks) some ac inar basal cells showed immunoreactivity to S-100 protein which rapidl y disappeared in the late developmental stage (33-40 weeks). Adult sal ivary glands were negative for S-100 protein. The S-100alpha subunit w as strongly positive in the glandular ducts and acini of both fetal an d adult glands. The S-100beta, although present in some acini and duct al cells during the late intermediate developmental stage, was rarely seen in the adult glands. GFAP and NSE was positive at the developing salivary epithelium in the early developmental stage (15-18 weeks). Th e above findings indicated that the developing salivary epithelia show ed transient appearance of the neuronal phenotype during active cytodi fferentiation stage of glandular acini and ducts. Therefore, after eva luation of normal developmental and neoplastic transformation of the s alivary glands a suggestion that neuronal differentiation of ductal re serve cells is responsible for the production of modified myoepithelia l cells in both normal developmental salivary gland and neoplastic tra nsformation is made.