Abstract: Objective To investigate the expression of gene solute carrier family 30 member 9 (SLC30A9) in human breast cancer，and to explore the correlation between expression of SLC30A9 mRNA and breast cancer. Methods 30 cases of surgically removed breast cancer tissue and their adjacent tissue，10 cases of normal breast tissue and 20 cases of benign breast lesion were enrolled in this study. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to detect the expression of SLC30A9 mRNA，and its clinical significances were analyzed. Results All the 90 samples expressed SLC30A9 mRNA. The average optical density ratios of SLC30A9 mRNA in the cancerous tissues，cancer-adjacent tissues，normal breast tissues and benign breast lesion tissues were 0.443±0.247，0.427±0.253，0.405±0.209 and 0.547±0.190 respectively，without significant difference (P＞0.05). Five of the 30 (16.7%) cancer tissues showed differential expression，among which 3 down-regulated and 2 up-regulated comparing to the normal counterparts. The average optical density rations of SLC30A9 mRNA were not statistically associated with age，clinical stages，lymphonode metastasis，distant metastasis and histopathological type (P＞0.05). Conclusion SLC30A9 expresses in a variety of breast tissues but only 16.7% cases are differential expression，suggestion it may not be the dominant gene for carcinogenesis of breast cancer.

Key words: Breast cancer, SLC30A9 gene, RT-PCR