Age-related proliferative activity in dermal melanocytic naevi detected by PCNA/cyclin expression.

A monoclonal antibody was used to demonstrate proliferating cell nuclear antigen in routine, formalin-fixed, paraffin-embedded tissue sections of dermal melanocytic naevi, including naevus naevocellularis partim lipomatodes, in different age-groups. The labelling indices of the melanocytic naevus cells were < 1% of those in the overlying epidermal basal cells, and showed a statistically significant decrease with ageing, and also in naevus naevocellularis partim lipomatodes, whereas the indices of the basal cells in the overlying interfollicular epidermis did not show any age-related changes.