Expression of G-CSF and GM-CSF in human meningiomas correlates with increased tumor proliferation and vascularization

The hematopoietic growth factors granulocyte- and granulocyte-macrophage colony stimulating factor (G-CSF and GM-CSF) are nowadays widely used in routine cancer therapies as potent factors to control radiation and chemotherapy induced neutropenia, a side effect that frequently endangers the success of tumor therapies. However, there is little information about the role of G-CSF and GM-CSF for tumor growth or progression. We were interested in the expression and potential role of both factors in human meningiomas, tumors of arachnoidal origin that account for about 20% of all primary intracranial tumors. Therefore, we analyzed immunohistochemically the protein expression of G-CSF, GM-CSF and their respective receptors in 30 meningioma tissues of different malignancy and histopathological type. Both factors and receptors were not expressed in the corresponding normal tissue. In contrast, G-CSF, GM-CSF and their receptors were expressed to a varying degree in human meningiomas. Increasing expression of both factors and receptors correlated significantly with enhanced proliferation in the tumor and thus with higher malignancy. In addition, a strong perivascular expression of G-CSF was associated with a highly vascularized tumor type. Thus, expression of both G-CSF and GM-CSF is associated with the expression of proliferation vascularization, two markers of an increasingly malignant tumor phenotype, suggesting a contribution of both factors to tumor progression.