Ricinus communis agglutinin I binding to the cell membrane in benign, premalignant and malignant epidermal lesions.

Membrane changes in keratinocytes were studied in a selected series of skin biopsies from 58 patients comprising cases of healing wounds, keratoachanthomas, actinic keratoses, Bowen's disease and squamous and basal cell carcinomas. The changes were demonstrated by means of a fluorescein-conjugated lectin ricinus communis agglutinin I, which specifically binds to beta-D-galactopyranosyl residues normally present on the keratinocyte surface. The RCA I binding equalled the binding of the normal epidermis in hyperplastic epidermis adjacent to healing wounds and in keratoachanthomas, but was slightly decreased in actinic keratoses and cases of Bowen's disease. In epidermal outgrowths from the edges of healing wounds and in squamous and basal cell carcinomas a heavy loss of RCA I binding was seen. The results are supported by previous in vivo and in vitro studies of normal and transformed cells, and it is suggested that the presented histochemical RCA I binding technique could be a valuable diagnostic tool.