de Vilhena AF, et al. - In the present study, the researchers verified the importance of Ki-67 as well as examined the associations between Ki-67 and other stromal biomarkers of vascular density. For this investigation, they analyzed Ki-67, CD34 and D2-40 in tumor tissues from 128 subjects with surgically excised typical carcinoid of the lung and to evaluate the amount of tumor staining for cellular proliferation (Ki-67), microvascular density (CD34-MVD) and lymphovascular density (D2-40-LVD), immunohistochemistry and morphometry were used. They found that a high Ki-67 proliferation rate was significantly correlated with tumors from patients with clinical stage IIb, IIIa and IV disease. They reported that quantitative staining of the tumor for Ki-67 and CD34-MVD served as prognostic factors, which were more relevant than the surgical and pathological stage. It was noted that Ki67 > 5% and CD34-MVD >7% staining comprises a subset of patients with higher death hazard.