Lai. Talve et al., BLEACHING OF MELANIN BEFORE IMAGE CYTOMETRY OF THE DNA CONTENT OF PIGMENTED SKIN TUMORS, Analytical and quantitative cytology and histology, 17(5), 1995, pp. 344-350
OBJECTIVE: To study the effect of bleaching of melanin with KMnO4 on t
he results of DNA image cytometry in pigmented skin tumors. STUDY DESI
GN: Image cytometry of nuclear DNA content teas performed on sections
from 14 melanocytic skin tumors stained with feulgen stain both with a
nd without prior bleaching with KMnO4. RESULTS: The nuclear staining i
ntensity of Feulgen stain tons lower in the bleached sections, but thi
s did not significantly affect the evaluation of ploidy. Heavy pig pig
mentation caused some false peaks in the histograms (4 of 28 measureme
nts made on unbleached slides). CONCLUSION: Blenching of sections with
KMnO4 can be useful when heavy melanin pigmentation would make DNA me
asurements impossible or difficult in image analysis cytometry. Bleach
ing is not advisable when only lightly pigmented tumors are analyzed i
f nuclei obscured by any pigment granules are to be avoided. In large
series containing both bleached and nonbleached specimens, statistical
analysis of these groups should be separated.