CXCL12 and pituitary gland adenoma: Finally, the evaluation of CXCR4 and CXCL12 expression in invasive and noninvasive pituitary adenoma specimens, by flow cytometry and immunohistochemical staining, demonstrated that the percentage of CXCR4- and CXCL12-positive cells was significantly higher in invasive pituitary adenomas [206].