结直肠癌中微卫星不稳定性与PD-L1表达的关系及临床意义

  目的  研究PD-L1在结直肠癌(colorectal cancer, CRC)中的表达及临床意义.  方法  选取2015年1月至2016年1月在郑州大学附属肿瘤医院接受CRC根治性手术的患者210例，分为微卫星高度不稳定（high-frequency microsatellite instability，MSI-H）、微卫星低度不稳定（low-frequency microsatellite instability，MSI-L）、微卫星稳定（microsatellite stable，MSS）3个组，采用免疫组织化学法检测各组织标本中细胞程序性死亡配体1（Programmed cell death 1 ligand 1，PD-L1）的表达，分析PD-L1在各型CRC中的表达特点。  结果  PD-L1在低分化CRC中的表达高于中、高分化CRC（P＜0.05），PD-L1在MSI-H的CRC中阳性率为75.8%，在MSIL/MSS中的阳性率为9.3%，两组比较差异具有统计学意义（P＜0.05）。  结论  PD-L1在部分CRC癌组织中阳性表达，尤其是在MSIH的CRC阳性率显著高于MSI-L及MSS的CRC。PD-L1阻断剂对MSI-H的CRC患者疗效可能更好。 

Relationship between expression of PD-L1 and microsatellite instability of colorectal cancer and its significance

Objective:To investigate the expression and clinical significance of PD-L1 in colorectal cancer (CRC). Methods:A total of 210 CRC patients who accepted radical surgery in our hospital from January 2015 to January 2016 were divided into three groups, namely, high-frequency microsatellite instability (MSI-H), low-frequency microsatellite instability (MSI-L), and microsatellite stable (MSS). The expression of PD-L1 was detected by immunohistochemistry, and the expression characteristics of PD-L1 in different types of CRC were analyzed. Results:CRC cases with low differentiation had a higher expression of PD-L1 than CRC patients with high differ-entiation (P<0.05). PD-L1 had a positive rate of 75.8%in the MSI-H group and a rate of 9.3%in the MSI-L and MSS groups, wherein the difference between the two groups was statistically significant (P<0.05). Conclusion:PD-L1 was positively expressed in some CRC tu-mor tissues, and its positive rate was significantly higher in MSI-H than in MSI-L and MSS. The therapeutic effect of a PD-L1 blocker for patients with MSI-H CRC might be preferable.