Abstract: Objective: To study the expression of Y14in human breast cancer and its significance. Methods:Western blot and RT-PCR were applied to detect the expression of Y14in human breast cancer tissue and tumor-adjacent tissue. Results: Y14expression was higher in human breast cancer tissue than in tumor-adjacent tissue ( P<0.05). Y 14expression was higher in pathological grade Ⅲtissue than in grade Ⅰand Ⅱtissue (P<0.05). Y 14expression in breast cancer tissue from patients with positive axillary lymph nodes was higher than in breast cancer tissue from patients without positive axil -lary lymph nodes ( P<0.05). No significant difference was found in Y14expression between breast cancer tissue from pa-tients with a tumor smaller than 2 cm in diameter and breast cancer tissue from patients with a tumor larger than 2 cm in di-ameter ( P<0.05). Conclusion:Y14expression is increased in breast cancer tissue. Y 14expression is increased in pathologi -cal grad Ⅲtissue and tissue from patients with positive axillary lymph nodes. There is no correlation between Y 14expres-sion and tumor size.