Establishment of an Orthotopic Transplantation Model of Tongue Carcinoma

Objective This study aims to establish an orthotopic transplantation model of rabbit tongue carcinoma and study its biological characteristics. Methods Tongue carcinoma was induced in purebred New Zealand white rabbits by exposure to 7,12-dimethylbenz[α]anthracene and mechanical stimulation. Fresh tumor tissues obtained from the induced tongue carcinoma model were then serially transplanted orthotopically into tongues of healthy rabbits. The tumor formation rate, invasion to surrounding tissues, regional lymph node metastases, and distant-organ metastases were investigated. Morphological observation by optical and electron microscopy, immunohistochemical examination, and chromosome analysis were performed. Results An orthotopic transplantation model of rabbit tongue carcinoma, designated as RSCC-2, was established. The tongue cancer was poorly differentiated squamous cell carcinoma. The tumor cell was hypotetraploid with a chromosome mode of 70. Immunohisto chemical examination showed positive staining for keratin. The tongue carcinoma survived in rabbits for 73 rounds of transplantation, using 465 rabbits in total. The average latent period was 12.5 days, and the average rabbit survival period was 37.5 days. The tumor formation rate was 10% to 20% in the first 20 rounds and increased gradually thereafter. After the 45th transplantation, the tumor formation rate and success rate of preservation in liquid nitrogen reached 100%. Regional lymph node metastases (35%) and lung metastases (20%) occurred after 50 rounds. In the advanced stage, tumors invaded the entire tongue. Animals suffered from weight loss and died of cachexia. Conclusions RSCC-2 is the first animal model for orthotopical transplantation of primary tongue carcinoma. It successfully simulates the clinical pathological process of primary tongue cancer in human, provides invaluable insights into the pathogenesis and metastasis mechanisms, and can be useful for evaluating new therapeutics for the treatment of tongue cancer.