On the other hand, a study by Gerstel and collaborators comparing the intratumoral vascular tree in spontaneous and transplanted mammary adenocarcinomas in CEACAM1 competent mice with CEACAM1 null hosts shows the former to have increased vascular densities and pericyte coverage, with increased tumor vascularization and angiogenesis [64]. The gene discussed is CEACAM1; the disease is breast adenocarcinoma.