We have applied
DNA flow cytometric analysis to
paraffin-embedded tissue sections of primary
malignant melanomas. Conventionally, flow cytometric analysis of
paraffin-embedded tissue sections has been done by the method of Hedley et al. We added ultrasound treatment to the method of Hedley et al. and a lower value of coefficient of variation was shown. Furthermore, a new technique, fluorescence in situ hybridization with a chromosome-specific repetitive
DNA probe, was used for the analysis of chromosomal numerical aberrations in the same
paraffin-embedded tissue sections. The
DNA flow cytometric analysis showed that in 8 cases six primary
malignant melanomas were of the
aneuploid pattern and two cases of
lentigo maligna (
melanoma in situ) were of the diploid pattern. By fluorescence in situ hybridization, the two cases with the diploid pattern had spots/nucleus of 1.28 and 1.12, and those with the
aneuploid pattern had spots/nucleus from 2.01 to 2.27. Only one nodular
melanoma in an
aneuploid case showed spots/nucleus of 1.71. These data indicate that fluorescence in situ hybridization with chromosome-specific repetitive
DNA probes can serve as a cytogenetic tool for the analysis of interphase nuclei of solid human
tumors and may be useful for the study of
tumor cell heterogeneity.