Tumours removed on day 14 p.i. and stained with anti-CD31, which selectively identifies microvessels and their long off shots reaching into the stroma, are shown in Figure 1A and B, respectively (microvessel density=3.5% for ACN/neo vs 11.2% for ACN/IFN-γ xenografts, P<0.001). The gene discussed is PECAM1; the disease is neoplasm.