Watkins et al., 2014 have used immunostaining-based methods to score vessel associated-glioma cells. Please read Watkins et al., 2014 article for more details.
REFERENCES:
Watkins et al., 2014. Disruption of astrocyte-vascular coupling and the blood-brain barrier by invading glioma cells. Nat Commun. 5, 4196. PMID-24943270; Full Text Link: nature, PMC4127490