BACKGROUNDKAI1 is a new identified metastasis-suppressor gene whose expression in many types of tumors has been reported. The aim of study is to investigate the role of KAI1 protein in development of lung cancer and its values in predicting the prognosis of lung cancer.

METHODSThe expressions of KAI1 protein were detected in benign pulmonary disease tissue, precancerous disease tissue, lung cancer tissue and metastatic lung cancer tissue in local lymph node using tissue microarray and immunohistochemical method. The relationship between expression of KAI1 protein and clinicopathological parameters of patients with lung cancer was analyzed by Chi-Square test and Fisher exact test.

RESULTSThe positive rate of KAI1 expression was 100.0% in 10 cases of benign pulmonary diseases, 66.7% in 12 cases of precancerous diseases, 24.7% in 89 cases of primary lung cancer and 0 in metastatic lung cancer tissue in local lymph node respectively. The KAI1 protein expression in primary lung cancer tissues had no remarkable relationship with age and gender of the patients and the location of cancer, but had significant relationship with the histological type and differentiated degree of tumor, P-TNM stages and lymph node metastatic status.

CONCLUSIONSThe abnormal expression of KAI1 protein may participate in malignant progression of lung cancer. Its downregulation may promote the invasion and metastasis of tumor cell. Detection of the expression of KAI1 protein may be helpful to predict the prognosis of lung cancer.