Abstract: Objective：To investigate the expression of protein gene product 9.5（PGP9.5）in endometrial cancer，and to find out the relationship between its expression and carcinogenesis，invasion and metastasis of endometrial carcinoma. Methods：The expression of PGP9.5 was detected by immunohistochemistry（Envision two steps ） in 60 patients of endometrial carcinoma and 10 patients of normal uterine tissues． Results：Of 60 endometrial cancer specimens examined，45 cases（75.0%）showed staining with PGP9.5 in most tumor cells，whereas PGP9.5 expression was detected only in 2 cases（20%） normal epithelium． The results of immunohistochemistry revealed that there were significantly correlations between the expression of PGP9.5 and the stages，the degree of differentiation，and the occurrence of lymph node metastasis respectively（P＜0.05）；but there were no correlation between the expression of PGP9.5 and age，histopathologic type（P＞0.05）. Conclusions：PGP9.5 may play an important role in the invasion and metastasis of endometrial cancer，and the invasion of endometrial cancer could be detected by PGP9.5，which may be a useful molecular marker．

Key words: Endometrial neoplasms, Immunohistochemistry, Oncogene proteins, Oncogenes, Gene expression