Experimental model of invasion and metastasis by orthotopic transplantation of oral squamous and adenoid cystic carcinomas into the tongue of nude mice.

Three squamous cell carcinoma (SCC) cell lines established from oral cancer, seven specimens of SCC and three of adenoid cystic carcinomas taken from the oral cavity during operations were transplanted into the tongues of nude mice. Metastases to the regional lymph nodes and the lungs were examined histologically. We were able to transplant every cell line or specimen of tissue into the tongue of nude mice, and found that cancer transplanted in the tongue invaded diffusely to the surrounding tissues without forming a capsule, and that the mode of invasion of the transplanted SCC was similar to that of the biopsy specimen of the patient from whom the material had been obtained. We also found that all three of the SCC cell lines, 3 of the 7 SCC specimens and 2 of the 3 adenoid cystic carcinoma tissues metastasized to the regional lymph node. SCC did not metastasize to the lung, but in two of the three adenoid cystic carcinomas we did see micrometastases to the lung. The study indicates that this method can be used as a model of metastasis in oral squamous cell carcinoma and adenoid cystic carcinoma to show the stages of metastasis in cancer.