Abstract: Objective To establish a model of metastatic nasopharyngeal carcinoma in nude mice and explore the correlation between ELAM-1 and metastasis of nasopharyngeal carcinoma. Methods Nasopharyngeal carcinoma 5-8F cell suspension was injected into the left hind paw pad of nude mice. Tumor formation，nude mice weight，the long and short diameter of the transplanted tumor were evaluated and tested. Sixteen human nasopharyngeal carcinoma-bearing nude mice were divided into metastasis group and non-metastasis group by continuous pathological section hematoxylin-eosin staining. ELAM-1 expression in transplanted tumor tissues was measured by immunohistochemistry. Results Tumor were formed in all mice，and the tumor formation rate was 100.0%. At last，ten nude mice showed metastatic tumors（metastatic rate，62.5%）. There was no significant difference in body weight between the two groups［（13.83±0.56） g vs （14.62±0.30） g，t=1.026，P=0.071） before the establishment of metastatic tumor model，then the tumor volume increased exponentially，and the growth rate of the tumors in the metastasis group was faster than that in the non-metastasis group. The tumor volume of the non-metastasis group was smaller than that of the metastasis group［（198.91 ± 163.29） mm³ vs （268.76 ±174.31）mm³ ，t=4.376，P=0.005）. ELAM-1 was positive in nasopharyngeal carcinoma xenografts，lymph node metastases and distant metastases，and mainly expressed in cell membrane. The optical density of transplanted tumors in the metastasis group was higher than that in the non-metastasis group（0.4497±0.0705 vs 0.0435±0.0082，t=4.388，P＝0.001）. Conclusions A metastatic model of nasopharyngeal carci-noma in nude mice with stability and high metastatic rate is successfully established. ELAM-1  is highly expressed in nasopharyngeal carcinoma xenografts in nude mice, promoting the growth and metastasis of transplanted tumors.

Key words: Nasopharyngeal neoplasms, ELAM-1, Nude mouse, Xenograft model, Neoplasm metastasis