In-vitro DNA synthesis of keratinocytes in normal human skin, psoriasis, seborrhoeic keratosis, Bowen's disease and basal cell carcinoma.

The DNA-synthesizing cells in benign and malignant keratotic diseases including psoriasis, seborrhoeic keratosis, Bowen's disease and basal cell carcinoma were studied. Cells in S-phase were labelled after small pieces of the lesions were incubated in tissue culture medium that contained 5-bromo-2'-deoxyuridine (BrdU). The labelling of DNA was analysed using the labelling index and pattern. Although the malignant diseases tended to show a higher DNA labelling index, neither this nor the loss of polarity alone was associated with malignancy. However, a higher DNA labelling index together with a loss of polarity was characteristic for malignancy.