Pleomorphic carcinoma（PC） is a rare tumor that usually has an aggressive clinical course and a poor　 prognosis. We investigated the hypothesis that PC　overexpresses angiogenic factors. Furthermore, we compared rates of expression of angiogenic factors in PC and adenocarcinoma（AD） of the lung. We collected each 11 cases of PC and AD in which the patients　underwent either a lung resection or at autopsy.　We immunohistochemically examined the expression　of angiogenic factors. Vascular endothelial growth factor（VEGF） and basic-fibroblast growth factor were expressed in many cases of both PC and AD, and there were no significant differences between the
two groups. However, the expression of cyclooxygenase（COX）-2 and hypoxia inducible factor-1α, and　the microvessel density, were significantly greater in　PC than in AD. These findings suggest that PC was associated with increased angiogenesis and that the
tumor tissue was in a hypoxic state.