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

Proliferative compartments of a tumour can be determined cytophotometricall y, by in situ hybridisation or by immunohistochemical detection of Ki67 ant igen. The main objective of this study was to analyse the proliferative act ivity during the progression of pigmented skin lesions with respect to diff erential 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). Compari son 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 grou p were highly significant. The results of forward and backward Cox regressi on were identical and only Ki67 showed an independent prognostic influence (p<0.001, coefficient in regression 0.02) with change in risk 2% and confid ence limit ranging between 1.1% and 2.9%.