Correlation of VEGF and COX-2 Expression with VM in Malignant Melanomas

OBJECTIVE To investigate the relationship between vascular epithelial growth factor (VEGF) and cyclooxygenase-2 (COX-2) in melanomas and the expressive difference of VEGF and COX-2 between melanomas with and without vasculogenic mimicry(VM).

METHODS Sixty cases of malignant melanomas embedded in paraffin were studied. The tumors were divided into a high-grade malignant group and a low-grade malignant group based on their tumor type, atypia and survival time of the patient. Then tissue microarrays were produced from these paraffin-embedded tumor tissues which were stained for VEGF, COX-2 and PAS. The difference in expression between VEGF and COX-2 in the malignant melanomas was compared using a grid-count. In addition, the tumors were also divided into mimicry and non-mimicry groups based on their PAS staining. Then the differences between the PAS positive and negative areas of the 2 groups were compared.

RESULTS In malignant melanomas with VM, VEGF and COX-2 expression was less in tumors in which VM was absent, but VEGF, COX-2 expression in high-grade malignant melanomas was higher than that in low-grade grade malignant melanomas. Expression of VEGF was correlated with COX-2 expression.

CONCLUSION VM exists in some high-grade malignant melanomas. The differences and relations between VEGF and COX-2 showed that some high-grade malignant melanomas possess a unique molecular-mechanism of tumor metastasis and blood supply.