Deoxyribonucleic acid content in the laryngeal mucosa with special reference to polyploid cell nuclei.

The DNA content was measured by microphotometry in morphologically normal squamous epithelium of the larynx, in hyperplastic epithelium of the vocal cords and in invasive squamous-cell carcinoma. The average nuclear DNA content in the squamous-cell carcinoma was elevated in comparison with that of normal epithelium, and the values showed a much wider dispersion. During premitotic DNA synthesis, the nuclear content of DNA is doubled. Polyploid cell nuclei with a nuclear DNA content of more than twice the model value (the stem cell of the tumour) are therefore a distinct sign of an abnormally elevated content of DNA. In morphologically normal epithelium no polyploid cell nuclei were revealed, while such nuclei were present in all cases of invasive squamous-cell carcinoma. Polyploid cell nuclei were found in six out of 20 patients with hyperplasia of the epithelium of the vocal cords. Among these six patients, manifest invasive carcinoma developed inthree, carcinoma in situ in one, while the condition remained benign in two, probably because the pathological tissue was completely removed. The presence of polyploid cell nuclei should thus arouse a strong suspicion of malignancy and calls for close supervision of the patient.