Orthotopic MPM histology. Fig. 3a. Frozen sections of tumors grown into the pleural cavity of nude mice injected with IST-Mes3 cells were stained with an anti-mouse CD31 antibody. Tumors were intensively stained revealing an intricate network of microvessels. Bar = 500 μm. Fig. 3b. H&E staining of tumor invading the lung. T: tumor, L: lung. Bar = 100 μm.