Objective:To study the expressive levels of KAI-1 mRNA，Kiss-1 mRNA and MTA1 in  the benign and malignant lesions of breast, and their clinicopathological significance.
Methods:We detected the expression levels of KAI-1 mRNA，Kiss-1 mRNA and MTA1 in the  sections from 60 cases of breast cancer and 30 cases of benign lesions of breast.
Results:The positive rates and scores of KAI-1 mRNA and Kiss-1 mRNA were significantly lower in breast cancer than those in benign lesions(P＜0.05 or P＜0.01); but MTA1 were the opposite(P＜0.05 or P＜0.01).  The positive rates and scores of KAI-1 mRNA and Kiss-1 mRNA were significantly higher in those with intra-ductal  breast cancer, histological tumor grade I or II, non-metastasis of lymph node, positive expression of ER, and negative expression of CA15-3 than in those with ductal invasive breast cancer, histological tumor grade III, metastasis of lymph node, negative expression of ER, and positive expression of CA15-3(P＜0.05 or P＜0.01) ;but MTA1 expression was the opposite(P＜0.05  or P＜0.01). Highly close correlations were found among the expressive levels of Kal-1 mRNA and Kiss-1 mRNA, but negative correlation between expression of MTA1 and expressions of Kal-1 mRNA and kiss-1 mRNA  in breast cancer tissues(P＜0.01). The  Kaplan-Meier survival analysis showed the five-year survival rates and median survival times were significantly higher in the positive cases of Kal-1 mRNA or Kiss-1 mRNA expression than those in the negative ones of Kal-1 mRNA or Kiss-1 mRNA expression in the breast cancer(P＜0.01); but those of  MTA1 were the opposite (P＜0.01).
Conclusions:The expressive levels of Kal-1 mRNA, Kiss-1 mRNA and MTA1 might be important biological markers on the carcinogenesis, progression, biologic behaviors and prognosis of  breast cancer.