Abstract: Objective To explore the expressions of metadherin （MTDH） and programmed cell death 4 （PDCD4） in breast cancer， and analyze their clinicopathological features in breast cancer. Methods The immunohistochemistry SP method was used to detecte the expressions of MTDH and PDCD4 of 65 cases of breast cancer tissues， 30 cases of adjacent normal breast tissues and 30 cases of breast fibroadenoma tissues. The clinicopathological variables of patients of breast cancer were collected and subsequently analyzed for their correlation with expressions of MTDH and PDCD4. Results The positive expression rate of MTDH was 72.3％ in breast cancer tissues， higher than 10.0％ of adjacent normal breast tissues and 20.0％ of breast fibroadenoma tissues （P＜0.05）， while the positive expression rate of PDCD4 was 41.5％ in cancer tissues， lower than 93.3％ of adjacent normal breast tissues and 86.7％ of breast fibroadenoma tissues （P＜0.05）. The expression rate of MTDH was related with age， TNM stage and axillary lymph node metastasis but unrelated with tumor size and location. The expression rate of PDCD4 was related with TNM stage and axillary lymph node metastasis but unrelated with age， tumor size and location. The MTDH expression was negatively correlated with PDCD4 （r=-0.595， P＜0.05）. Conclusion There is high expression of MTDH and low expression of PDCD4 in breast cancer. And they are related with TNM stage and axillary lymph node metastasis， indicating an important role in the occurrence and development of breast cancer.