DNA flow cytometry of the epidermis of patients with multiple epidermal carcinomas.

We used DNA flow cytometry to determine whether the uninvolved skin of twenty-four patients with multiple epidermal cancers differed from normal skin with regard to its epidermal cell kinetics. We also studied the relationship between the cell kinetics and the type of cancer, previous exposure to ionizing or UV radiation, previous arsenic intake, skin type and coexisting psoriasis. Both exposed and unexposed skin was studied. In thirteen patients the S and G2M fractions of a monoclonal tumour were compared with the values in unexposed and exposed skin. The S and G2M fractions increased progressively from unexposed skin to exposed skin to tumour tissue. Patients who had developed both squamous and basal cell carcinoma differed from those who had developed only basal cell carcinoma by having a significantly higher G2M fraction in the exposed skin, and significantly higher S and G2M fractions in the unexposed skin. Patients exposed to ionizing radiation tended to show higher G2M fractions in exposed skin compared with the remaining individuals (P = 0.06). The presence of psoriasis, exposure to UVR or sunlight and previous arsenic ingestion did not appear to affect the results.