EXPRESSION OF CYCLOOXYGENASE-2 IN MALIGNANT PHEOCHROMOCYTOMAS AND ITS RELATIONSHIP WITH MICROVESSEL DENSITY

Objective To investigate the expression of cyclooxygenase-2 (Cox-2) and microvessel density (MVD) in benign and malignant pheochromocytomas, and the relationship between Cox-2 and MVD. Methods Specimens and clinical data from 38 patients (21 benign and 17 malignant pheochromocytomas) were studied. Slides of normal adrenal glands in nephrectomy specimens from another 20 patients with benign renal tumors were used as control. Immunohistochemical technology was performed to detect the Cox-2 and MVD in all specimens. Results Expression of Cox-2 was observed in 5 of the 21 benign pheochromocytomas (23.8%), and in 14 of the 17 malignant (82.4%). No expression of Cox-2 was observed in control slides. There were significant differences of Cox-2 expression between benign and malignant pheochromocytomas, as well as between malignant pheochromocytomas and control (P<0.05). Expressions of MVD were 36.41±13.00, 21.43±8.05, and 13.36±4.34 in malignant, benign pheochromocytomas, and in control, respectively. Conclusion Cox-2 may contribute to the invasive characteristics of malignant pheochromocytomas and be used as a marker to distinguish malignant from benign pheochromocytomas. Expression of MVD in malignant pheochromocytomas was directly correlated with Cox-2.