PRIMARY MALIGNANT-MELANOMA OF THE SKIN - RELATIONSHIPS OF NUCLEAR-DNACONTENT, NUCLEAR MORPHOMETRIC VARIABLES, CLARK LEVEL AND TUMOR THICKNESS

OBJECTIVE: To investigate how nuclear morphometric variables, tumor th ickness (measured according to Breslow), invasion depth (classified ac cording to Clark), nuclear DNA content and type of DNA histogram are a ssociated with each other in primary malignant melanomas of the skin. STUDY DESIGN: Image analysis DNA cytometry and nuclear morphometry wer e performed on 85 primary skin melanomas. The relationships of size, s phericity and DNA content of melanoma cell nuclei; melanoma thickness; and Clark level were analyzed in detail. The effect of melanin bleach ing on DNA cytometry results was studied. RESULTS: Melanoma thickness correlated with nuclear size in aneuploid, but not diploid, melanomas. The prevalence of aneuploidy did not increase with tumor thickness. I n aneuploid melanomas the proportion of cells with higher-than-diploid and higher-than-tetraploid DNA content increased with tumor size. CON CLUSION: Aneuploidy is as common in thin as in thick melanomas. Geneti c instability in aneuploid melanomas correlates with melanoma thicknes s. This correlation in aneuploid melanomas partially explains the corr elation between nuclear size and melanoma thickness. In diploid melano mas no correlation was observed between nuclear size and melanoma thic kness. DNA cytometry is it valuable tool for studies on the background of phenotypic changes in skin melanomas.