Expression and secretion of neural cell adhesion molecules by human pituitary adenomas

Neural cell adhesion molecules (NCAMs) are found predominantly in neural, m uscle and endocrine cells. Recent interest has focused on their potential r ole in tumorigenesis. We have analysed the expression and secretion of NCAM in a series of 48 human pituitary adenomas. Immunocytochemical analysis of 19 adenomas demonstrated NCAM expression in all tumours with, in each case , diffuse cytoplasmic staining being found with variable membrane accentuat ion. There were no apparent differences in the expression of immunoreactivi ty seen on sections between individual tumours. Cell culture media from 43 dispersed human pituitary tumours were analysed by immunoassay for the secr etion of soluble NCAM and all the pituitary hormones. In contrast to the im munocytochemical studies, soluble NCAM was released from only 27% of human pituitary tumours, but this was not related to tumour type nor was the amou nt of soluble NCAM released correlated with the amount of pituitary hormone secreted by each adenoma. NCAM expression is common to all human pituitary adenoma types and the observed differences in release of soluble NCAM betw een individual tumours may reflect different molecular mechanisms, altering adhesive interactions between normal and adenomatous tissue.