Cyclin A expression in superficial spreading malignant melanomas correlates with clinical outcome

Abstract

The present study analysed by immunohistochemistry the protein level of cyclin A and Ki‐67 in a panel of paraffin‐embedded tissue obtained from 172 primary (110 superficial and 62 nodular) and 73 metastatic melanomas, and ten benign naevi. Since cyclin A exists in the same quaternary complex in the S‐phase of the cell cycle as the cdk inhibitor p21^WAF1/CIP1, the levels of the two proteins were compared. Cyclin A and Ki‐67 were heterogeneously expressed in the malignant tumours, whereas in benign naevi, only rare positive cells were detected. In superficial spreading melanomas, the cyclin A level was related to tumour thickness, with less expression in thinner lesions (ppWAF1/CIP1 (p=0.01) scores. Multivariate analysis showed that in addition to the depth of the primary tumour, the protein level of cyclin A was an independent indicator of relapse‐free period (thickness, pp=0.0003). In contrast, in nodular melanoma, the cyclin A level was associated with Ki‐67 expression, but neither cyclin A nor Ki‐67 was related to tumour thickness (cyclin A, p=0.06; Ki‐67, p=0.61) and neither had any impact on relapse‐free (cyclin A, p=0.64; Ki‐67, p=0.32) or overall (cyclinA, p=0.94; Ki‐67, p=0.45) survival. In conclusion, the results indicate that cyclin A is a strong prognostic factor for patients with superficial spreading melanomas. In nodular melanomas, the proliferation rate seems to have little impact on disease progression. Copyright © 2001 John Wiley & Sons, Ltd.