Abstract
This study was performed to obtain the index for the clinical malignancy of oral cancers as well as that for the potential of malignant change in oral precancerous lesions by analysing the nuclear DNA content and nuclear area and examining the relationship of these parameters to the clinical and pathological findings.
Subjects enrolled in this study were consisted of 57 cases of oral squamous cell carcinoma, 13 cases of leukoplakia, 10 cases of verrucous hyperplasia and 6 cases of normal oral mucosa. Cell samples were obtained by smear and imprint in general but isolated from thick paraffin sections of biopsy specimens in some cases as occasion demanded. The nuclear DNA content and nuclear area were simultaneously determined by Vickers M 86 scanning microdensitometer after Feulgen staining. The nuclear DNA content of epithelial cells was calculated referring that of lymphocyte as control to be 2.0 C.
The results were summarized as follows:
1. The DNA histogram revealed that the normal oral mucosa had a high, distinct peak at 1.5-2.0 C. Cells over 4.0 C were not observed. The nuclear area was approximately 40μ2.
2. In the case of squamous cell carcinoma, the variations of nuclear DNA content and nuclear area became larger with the increased values of them, however, the variation by individual cases was also large. Patients with rapid progress of tumorigenesis and high degree of histological atypia had increased average values of nuclear DNA content and its variance, high frequency of cells over 4.0 C, and enhanced variance of nuclear area. In addition, patients with 2 peaks or more in the DNA histogram or those with high correlation of nuclear DNA content to nuclear area were apt to have poor prognosis.
3. The nuclear DNA content and nuclear area in cells from cases of papilloma or leukoplakia with simple hyperkeratinization were the same as normal mucosa or else increased slightly. However, the average nuclear DNA content and its variance, frequency of cells more than 4.0 C, distributions of nuclear DNA content and nuclear area in cells from suspected malignant verrucous lesion and leukoplakia accompanying carcinogenesis in part resembled to those of squamous cell carcinoma.
From these findings mentioned above, determinations of the nuclear DNA content and nuclear area of cells from oral cancers and oral precancerous lesions seem to have an important significance in the evaluation of clinical malignancy and malignant potential.
