Proliferative activity in the progression of pigmented skin lesions, diagnostic and prognostic significance

Proliferative compartments of a tumour can be determined cytophotometrically, by in situ hybridisation or by immunohistochemical detection of Ki67 antigen. The main objective of this study was to analyse the proliferative activity during the progression of pigmented skin lesions with respect to differential diagnostic and prognostic applications. The material investigated consisted of 209 pigmented skin lesions (31 naevi, 30 dysplastic naevi, 106 primary melanomas, 20 lymphatic and 22 organ melanoma metastases). Comparison of the ratios of cells in the S-phase gained by two different methods (cytometry, in situ hybridisation) did not show any significant differences. The correlations between Ki67 and S-phase indices in every diagnostic group were highly significant. The results of forward and backward Cox regression were identical and only Ki67 showed an independent prognostic influence (p < 0.001, coefficient in regression 0.02) with change in risk 2% and confidence limit ranging between 1.1% and 2.9%.