Axl and growth arrest-specific gene 6 are frequently overexpressed in human gliomas and predict poor prognosis in patients with glioblastoma multiforme.

Purpose: The receptor tyrosine kinase Axl has recently been identified as a critical element in the invasive properties of glioma cell lines. However, the effect of Axl and its ligand growth arrest--specific gene 6 (Gas6) in human gliomas is still unknown.

Experimental Design: Axl and Gas6 expression was studied in 42 fresh-frozen and 79 paraffin-embedded glioma specimens by means of reverse transcription-PCR and immunohistochemistry.