A Cell Kinetic Study on Squamous Cell Carcinoma in the Oral Cavity : Analysis by DNA Cytofluorometry Combined with 3H-thymidine Autoradiography

In order to evaluate the clinical significance of the cell population kinetics of squamous cell carcinoma in the oral cavity, a cell kinetic study was performed by means of DNA cytofluorometry combined with 3H-thymidine (3H-TdR) autoradiography. Fifty-three cases of squamous cell carcinoma in the oral cavity were investigated. The biopsied cancer tissues were labeled with 3H-TdR in vitro and then histological sections were made for autoradiography. 3H-TdR labeling index (LI) and mitotic index (MI) of the cancer cells at the tumor-host boundary were measured from hematoxylin-eosin stained autoradiographs. The nuclear DNA contents of labeled and unlabeled cancer cells were measured from Feulgen stained autoradiographs, and then DNA histograms were estimated from those DNA contents. Subsequently the proportion of the cells in each cycle phase of the cancer cells was analyzed from those DNA histograms. The following results were obtained. (1) The values of LI, MI and nuclear DNA content of each carcinoma in the 53 patients varied greatly from case to case. (2) As the DNA histograms of each carcinoma showed various widths of distribution from case to case, all of them were graded in four patterns such as P-I (diploid pattern), P-II (hyperdiploid pattern), P-III (narrow aneuploid pattern) and P-IV (wide aneuploid pattern). The nuclear DNA contents of 3H-TdR labeled cells in 46 carcinomas with P-I?III were interspersed between the diploid and tetraploid range, whereas a number of labeled cells in 7 carcinomas with P-IV were distributed beyond the tetraploid. As the analysis of the cell cycle in carcinoma with P-IV seemed to be difficult, the proportion of the cells in each cycle phase (G0G1, S, G2M) were estimated from the DNA histogram of 46 carcinomas with P-I?III. (3) The grades of DNA patterns showed a good correlation with LI, MI and the proportion of the cells in G0G1, S, and G2M. However, those values of carcinoma with P-III varied from case to case in comparison with those of carcinoma with P-I and P-II. Therefore P-III was further divided into two patterns of P-IIIa (LI