Endothelial cells in abnormal tumour vessels are not homogeneous, and differ in phenotype from their non-tumour counterparts.30,62 Although transcriptomic profiles can vary between tumour vessels and normal vessels, few genes directly associated with the abnormal neovasculature have been identified.59 The regulator of G-protein signalling 5 (Rgs5) has been shown to be a master gene for abnormal vascular morphology in the tumour.63 Rgs5 is expressed in a variety of organs and upregulated on blood vessels in Rip1-Tag5 tumours. The gene discussed is RGS5; the disease is neoplasm.