Objective  To investigate the MUC2 and MMP-9 expression in breast carcinoma tissue and to analyze its relationships with clinical characteristics.

  Methods  Reverse transcription PCR was applied to detect the MUC2 and MMP-9 mRNA expression in benign breast diseases and breast cancer. The expression levels of MUC2 and MMP-9 were measured by Western blot. The correlations of MUC2 and MMP-9 with clinical characteristics and the relationship between these two proteins were analyzed.

  Results  The grayscale bands of the MUC2 and MMP-9 mRNAs in breast tumors were significantly higher than those in benign breast diseases. The expression levels of MUC2 mRNA in benign breast diseases and breast carcinoma were 2.9% (2/68) and 39.8% (53/186), respectively (P < 0.05), whereas those of MMP-9 mRNA were 13.2% (9/68) and 73.1% (136/186), respectively (P < 0.05). Moreover, the MUC2 and MMP-9 expression was significantly lower in benign diseases than in breast tumors. The MUC2 and MMP-9 mRNA expressions were correlated with the tumor type and lymph-node metastasis of breast carcinoma, respectively (P < 0.05). In addition, the MMP-9 mRNA expression was correlated with histological grade and tumor size. However, no significant associations were found between gene expression and patient age (P>0.05). The MMP-9 expression had a significantly inverse correlation with MUC2 (r= -0.814; P < 0.001).

  Conclusion   The MUC2 and MMP-9 expression may be indicators of breast cancer. They may be suitable indicies for diagnosis and treatment of breast carcinoma.