Fig. 1

Histopathologic sections obtained from melanoma tumor autopsy in mouse stained with H&E (10–100 x magnifications). Representative histological analysis of tumor tissue from melanoma-bearing mice (n = 5). In panel a (10× magnification) the yellow circles indicate areas of intensive melanin pigmentation, a red circle indicates an area of hemorrhage and a green arrow highlights an invasive mitotic melanocyte. Its condensed genetic material (chromatin) indicates this as being mitotic. In panel b (10× magnification) the yellow circle shows an area containing many mitotic melanocytes and the neighboring red box area shows vascular invasion by some of the invasive melanocytes. In panel c (40× magnification) the upper black arrow shows a large mitotic melanocyte (with segmented chromatin and genetic material) and the lower green arrow shows melanin pigmentation (dark brown areas). In panel d (100× magnification) the upper black arrow shows a large mitotic melanocyte (with purple-stained genetic material) and the lower green arrow shows melanin pigmentation (dark brown area). All mice showed similar melanoma features