Immunofluorescent Light Micrograph of melanoma cancer cells and fibroblasts, cultured from a human tumour. A fibroblast (star-shaped cell, at centre), forms connective tissue to support other cells. Actin fibres (green) around it help provide this supportive network. Smaller melanoma cells have a large nucleus (blue); cytoplasm is orange. Derived from melanin-forming cells of the skin, they are highly malignant & divide rapidly (seen at upper right). Immunofluorescence is a staining technique which uses antibodies to attach fluores- cent dyes to specific tissues and to molecules within the cell.Mag:x200 at35mm,x340 at 6x4.5size.