Matrix metalloproteinase-9 secretion by human pituitary adenomas detected by cell immunoblot analysis

Twenty-two pituitary adenomas were examined on the secretion of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) using a cell immunoblot assay, and discussed regarding an association between cavernous sinus invasion and the secretion of these proteins. The cell immunoblot assay, a kind of immunoblot procedure, is able to detect proteins at the single cell level and to detect the incidence of tumour cells secreting the target proteins in the total tumour cell population. The incidence of tumour cells secreting MMP-9 was significantly higher in invasive adenomas than in noninvasive ones. On the other hand, TIMP-1 secretion was not detected in any adenomas in this study. This result suggested that MMP-9 secretion, and especially the number of MMP-9-secreting cells, may be associated with cavernous sinus invasion of pituitary adenomas.