Correlation between SPARC (Osteonectin) expression with immunophenotypical and invasion characteristics of pituitary adenomas

Abstract

Pituitary adenomas are the third most common intracranial tumors. Invasive adenomas account for only 0.1-0.2% of pituitary tumors. SPARC is a matrix glycoprotein that plays a role in progression and invasiveness of neoplasms. In this study, we examined the potential role of SPARC in invasive pituitary adenomas. Forty pituitary adenomas have been examined with histopathological and immunohistochemical techniques. The cohort has been classified into two groups as invasive (n=25) and non-invasive (n=15) utilizing the Hardy classification. Formalin fixed tissues have been stained with hematoxylin eosin. Ki-67, p53, and SPARC monoclonal antibodies have been used. We did not detect any significant difference on Ki-67, SPARC, and p53 expression patterns correlating with the pathological subtype or invasiveness. Only 24% of invasive adenomas had Ki-67 levels over 1%. A total of 67.7% non-invasive adenomas had Ki-67 levels below 1%. We did not detect any relation between SPARC levels and invasiveness of pituitary adenomas. Absence of significant SPARC expression in tumor progression, sellar dilatation, erosion and destruction suggest that SPARC scores are not related with invasiveness or progressiveness of pituitary adenomas.