Vergleichende quantitativ-cytochemische Untersuchungen �ber den Desoxyribonucleins�ure-und Nucleohiston-Gehalt von Basalzellepitheliomen

Clonal heterogeneity in curetted human epidermal cancers and precancers analysed by flow cytometry and compared with histology

DNA frequency distributions analysed by single nuclei flow cytometry were studied in sixty-five curetted human epidermal tumours, i.e. five actinic keratoses (AK), seven Bowen's diseases (BO), nine squamous cell carcinomas (SCC), forty-three basal cell carcinomas (BCC) and one baso-squamous carcinoma (BSC). Seventy-five per cent (16/21) of the samples with squamous cell differentiation (AK, BO and SCC) showed features suggestive of more than one stem cell population, against 24% of the pure BCC samples (11/43). The DNA indices for the tumours, i.e. the ratio between the DNA content of the tumour stem cell line G1 cells and normal epidermis G1 cells were calculated. For BCC and SCC a preponderance was found for near-diploid and near-tetraploid cell clones. The precancerous lesions contained clones with more broadly scattered DNA indices. The fractions of cells in S and G2M and S + G2M phases were calculated for the samples with only one detectable stem cell population. For the squamous cell tumours and the nodular (but not the superficial) BCC, these fractions were significantly different from the unaffected skin of patients with multiple epidermal cancers. The usefulness of cell cycle fraction determinations for curetted tumours is discussed.

DNA measurements by single nuclei flow cytometry in human actinic skin lesions

A basal cell carcinoma, a Bowenoid carcinoma and clinically normal nonexposed skin from a 76-yr-old male with numerous epidermal tumors on sun-damaged skin were investigated by DNA flow cytometry and the results were compared with data obtained from normal skin of a control group. From each type of skin lesion 3 different biopsies were examined. Each of the DNA frequency distribution histograms showed bimodal configuration revealing no more than one DNA stem line, which was diploid in the unaffected skin and the Bowen carcinoma and hyperdiploid in the basal cell carcinoma. The 3 different types of skin could be clearly separated by means of at least 1 of 3 parameters: S-fraction, G2 + M fraction or S/G2 + M index. The S/G2 + M index came out as the most sensitive discriminator for the tumors. The S-fraction level was higher in the clinically normal skin of the investigated male than in the control group and further high in the tumors.