为探讨PD-L1在人结直肠癌（colorectal cancer，CRC）组织中的表达情况以及其与患者临床病理特征之间相关性，用免疫组化法检测CRC患者石蜡样本中PD-L1的表达情况，分析其与分化程度及转移情况之间的关系。ELISA检测CRC组织和癌旁组织PD-L1蛋白表达情况。结果显示，PD-L1的表达与肿瘤分化程度显著相关，随着分化程度由高到低，PD-L1的表达也越来越强（P<0.01），但并未发现PD-L1表达和转移情况的相关性（P>0.05）。CRC组织的PD-L1表达水平显著高于癌旁组织（P<0.001）。该研究提示，PD-L1在CRC癌组织相对于癌旁组织过表达，且其表达与肿瘤分化程度呈正相关，其有望成为判断结直肠癌患者临床预后的指标之一。

This study aims to investigate the expression of PD-L1 in human colorectal cancer (CRC) and its correlation with clinicopathological characteristics. PD-L1 expression was measured by immunohistochemistry of CRC patients and analyzed to reveal its relationship with histological tumor grade and metastasis. PD-L1 expressions in CRC tissue and para-cancerous tissue were measured by ELISA. The results showed that PD-L1 expression was significantly correlated with histological tumor grade. PD-L1 expression increased with the decreasing of tumor differentiation levels from high to low (P<0.01). However, there was no apparent correlation between PD-L1 expression and metastasis condition (P>0.05). The expression of PD-L1 in CRC tissue was significantly higher than that in para-cancerous tissue (P<0.001). The study suggests that PD-L1 expression is higher in CRC tissue, compared to that in para-cancerous tissue, and PD-L1 expression is significantly associated with histological tumor grade, making it a potential indicator to assess the clinical prognosis of CRC patients.