Study on the Expression Levels of CXCR4, CXCL12, CD44, and CD147 and Their Potential Correlation with Invasive Behaviors of Pituitary Adenomas

Objective To evaluate the factors of CXCR4, CXCL12, CD44, and CD147 as early potential diagnostic biomarkers by determining their expression levels in invasive and non-invasive pituitary adenomas. Methods Fresh pituitary adenoma specimens were collected from 35 pituitary adenoma (21 invasive and 14 non-invasive) patients who underwent surgical treatment in our Neurosurgery Department between January and April of 2009. The expression levels of CXCR4, CXCL12, CD44, and CD147 were evaluated firstly by flow cytometry, fluorescence microscopy in single cell suspensions, and then by immunohistochemical staining of paraffin tissue sections. Results Flow cytometric analyses showed that the percentage of CXCR4-and CXCL12-positive cells from invasive pituitary adenomas (IPA) was significantly higher in the single cell suspensions than that from non-invasive pituitary adenomas (nIPA) (P<0.05). Immunohistochemical staining revealed that CXCR4 and CXCL12 staining index scores of the invasive pituitary adenomas were significantly higher than those of the non-invasive pituitary adenomas (P<0.05). In contrast, neither flow cytometry nor immunohistochemical staining demonstrated significant difference between CD44 and CD147 expression levels, respectively. Conclusion Expression levels of CXCR4 and CXCL12 are correlated with the invasiveness of pituitary adenomas. Therefore, rather than CD44 and CD147, CXCR4 and CXCL12 may potentially serve as biomarkers for early detection of pituitary adenomas.