Abstract: Objective To investigate the expression of urotensin Ⅱ(UⅡ) in the lung cancer tissue from surgical resection of lung cancer patients, and to detect the relationship between UⅡ expression and pathologic types and the clinical stages of lung cancer. Methods The expression rates of UⅡof 45 lung cancer tissues and 20 inflammatory pseudotumor were measured by immunohistochemical assay, and the relationship between UⅡexpression and the pathologic types and clinical stages of lung cancer was analyzed. Results UⅡwas mainly distributed in lung cancer cell cytoplasm, which was tanyellow particles. The positive expression rate of UⅡin nonsmall cell lung cancer was 61.3%(19/31)， which was higher than that in small cell lung cancer（7.1%,1/14） and pulmonary inflammatory pseudotumor（15.0%,3/20）(P<0.01).The positive expression rate of UⅡ was 100% in adenocarcinoma. The positive expression rate of UⅡin staging Ⅲ nonsmall cell lung cancer（85.7%） was higher than that of staging Ⅰ （16.7%）(P<0.05). Conclusion UⅡ exists in the cytoplasm of lung cancer cells, and the expression of UⅡis correlated with the pathological type and TNM staging of lung cancer.

Key words: Lung neoplasms, Immunohistochemistry, UrotensinⅡ