Development of a new invasion and metastasis model of human oral squamous cell carcinomas.

A new model was devised in order to establish an in vivo model for oral carcinoma that exhibits significant local invasion and metastasis. One hundred and fifty-two nude mice had tumour cells from one of two established oral squamous cell carcinoma (SCC) cell lines (OSC-19 and OSC-20) implanted into the tongue or the oral floor via an intra-oral route and, as a control, the subcutaneous tissue of the back. The back tumours showed an expansive growth pattern, lacking significant invasion of surrounding tissues. In contrast, the tumours implanted into the tongue or the oral floor exhibited invasive growth and the histological appearance was similar to that of the original tumours. Moreover, regional neck lymph node and pulmonary metastases were observed in this model. Regional neck lymph node metastases were detected in 81.0% of mice implanted with OSC-19 cells and in 13.6% of mice implanted with OSC-20 cells. OSC-19 and OSC-20 cells showed pulmonary metastases in 9.5 and 9.1% of mice, respectively. These results suggest that this intra-oral implantation model is valuable in the study of the mechanism of invasion and metastasis of oral SCC.