Abstract
Measurements of cell cycle kinetics using an immunoperoxidase method employing monoclonal anti‐bromodeoxyuridinc (BrdU) antibody were compared with an autoradiographic method using [3H]‐thymidine. The methods were applied to epithelial cells grown from explants of normal skin and basal cell carcinoma (BCC), and to fibroblasts from normal skin, hypertrophic scar and keloid. In normal keratinocytes the number of peroxidase‐positive cells was higher than the number incorporating [3H]‐thymidine, because of the presence of labelled cells in the centre of the explants in the former. The epithelial cells from BCC gave a mean (± SD) of 4.9 ± 1.2% peroxidase‐positive cells, while no cells were labelled with [3H]‐thymidine. In dermal fibroblasts from normal skin and hypertrophic scar the percentages of peroxidasc‐positive cells did not differ significantly from the [3H]‐thymidine labelling indices. The immunological method has advantages over [3H]‐thymidine autoradiography in that it avoids radioactive material and the proportion of cells labelled by the two methods is the same.