目的　探讨P2 1[WAF1] 在乳腺癌中的表达及其与组织学分级和预后的关系。方法　采用免疫组化LSAB法检测 15 2例乳腺癌组织P2 1[WAF1] 蛋白的表达水平。结果　在 15 2例乳腺癌组织中P2 1[WAF1] 蛋白阳性 61例 ,其中低表达 43例 ,高表达 18例 ;P2 1[WAF1] 蛋白的表达与乳腺癌组织腺管形成、细胞核多形性、核分裂象计数和组织学分级呈正相关 ;单因素生存分析显示P2 1[WAF1] 高表达组生存期低于低表达组 (χ2 =6 92 ,P <0 0 1)。结论　P2 1[WAF1] 在乳腺癌中的不同表达水平可能与组织学分级和预后有关 Objective To investigate the expression of P2 1 [WAF1] in breast cancer and its relationship with histological grade and prognosis. Methods The expression of P2 1 [WAF1] protein in breast cancer tissues was detected by immunohistochemical LSAB method. Results 61 cases of P2 1 [WAF1] protein were positive in the tumors of breast cancer, of which 43 cases were lowly expressed and 18 were highly expressed. The expression of P2 1 [WAF1] protein was associated with the formation of ducts and pleomorphism of breast cancer tissue. There was a positive correlation between mitotic counts and histological grading, and univariate survival analysis showed that the survival time of P2 1 [WAF1] high expression group was lower than that of low expression group (χ2 = 6 92, P <0 01). Conclusion Different expression levels of P2 1 [WAF1] in breast cancer may be related to histological grade and prognosis