Flow cytometric analysis of primary and metastatic squamous cell carcinomas of the oral and maxillofacial region.

OBJECTIVE

To elucidate characteristic changes in nuclear DNA content and cell kinetics in primary lesions and metastatic lymph nodes of squamous cell carcinomas of the oral and maxillofacial region.

MATERIALS AND METHODS

Materials used were paraffin-embedded tissue specimens obtained from 96 primary lesions of 96 patients and 85 metastatic lymph nodes of 41 patients with squamous cell carcinoma of the oral and maxillofacial region. Single cell suspensions for flow cytometry analysis were prepared, and cell cycle analysis was performed.

RESULTS

The incidence of aneuploidy in 41 carcinomas with metastasis was 39%, which was significantly higher than the 16% incidence in 55 carcinomas without metastasis. In terms of T classification and mode of invasion, the incidence of aneuploidy and metastasis increased with the increase in gradings. Forty-four of 46 metastatic lymph nodes associated with 25 diploid primary tumors remained diploid, whereas a shift down to diploidy was observed in 25 of 39 metastatic lymph nodes associated with 16 aneuploid primary tumors. The incidence of aneuploidy and S-phase fractions of 85 metastatic lymph nodes in 41 patients were 19% and 9.6%, respectively. The values were significantly lower than the 39% and 14.3% of the corresponding primary lesions.

CONCLUSIONS

The chance of evolution of metastatic cell lines is higher in aneuploid carcinomas than diploid carcinomas, possibly because the former are more heterogenous; however, most cell lines responsible for causing lymph node metastasis are diploid.