Prognostic significance of standard deviation and coefficient of variation of DNA quantity of malignant melanoma cell nucleus.

The nuclear DNA content of 47 primary malignant melanomas was measured by DAPI (4', 6-diamidino-2-phenylindole) -DNA microfluorometry and mean of the nuclear DNA content (DNA index: DI), standard deviation (SD), coefficient of variation (CV) were calculated. The Kaplan-Meier life table method revealed that the DI and the SD significantly correlated with the patient survival. A Cox proportional hazards multivariate analysis demonstrated that the relative death rate of the SD was 5.2, but it lost the significance when the DI was applied to the model. Since the correlation coefficient between the DI and the SD was high (0.835), the SD was a dependent variable on the DI. To evaluate nuclear DNA content as a simple value, the DI is the most useful among the three.