免疫组化法和聚合酶链反应法对结直肠癌微卫星不稳定性诊断价值

Diagnostic value of immunohistochemistry and polymerase chain reaction for microsatellite instability in colorectal cancer

目的比较免疫组化法(IHC)和聚合酶链反应法(PCR)在诊断结直肠癌患者微卫星不稳定性(MSI)时的一致性和可靠性。方法回顾性分析2019-01-17-2021-12-22湖南航天医院普外科和消化内科135例行转移性切除术或活检的结直肠癌患者临床资料和病理标本。从每例患者中分别采集肿瘤组织和距离肿瘤边界至少5 cm的正常结肠黏膜组织,并进行固定、包埋和切片处理。采用IHC和PCR两种方法对组织样本进行MSI检测。结果135例患者中有125例错配修复功能正常(pMMR),10例错配修复功能缺失(dMMR)。与pMMR患者相比,dMMR患者的肿瘤体积较大,更常发生于结肠右半部,且更易为黏液腺癌或低分化癌。在dMMR患者中,有4例出现PMS2缺失,3例呈现片状PMS2表达。PCR检测发现有8例患者属于微卫星高度不稳定(MSI-H),1例患者属于微卫星低不稳定(MSI-L),1例患者属于微卫星稳定(MSS)。具有PMS2缺失或弱表达的患者中,62.5%(5/8)为MSI-H。IHC和PCR检测结果的一致性分析Kappa值为0.943,P<0.001。结论IHC和PCR在诊断结直肠癌患者MSI状态时具有较高的一致性和可靠性。然而,在IHC检测为阴性或弱阳性时,建议进行PCR检测以避免漏诊。综合应用这两种方法有助于提高结直肠癌患者的MSI检测准确率。

Objective To compare the consistency and reliability of immunohistochemistry(IHC)and polymerase chain reaction(PCR)methods in diagnosing microsatellite instability(MSI)in patients with colorectal cancer.Methods A retrospective analysis was conducted on clinical data and pathological specimens of 135 patients with colorectal cancer who underwent metastatic resection or biopsy in the Department of General Surgery and Gastroenterology at Hunan Aerospace Hospital from January 17,2019 to December 22,2021.Tumor tissue and normal colon mucosal tissue at least 5 cm away from the tumor boundary were collected from each patient,and fixed,embed,and sliced.IHC and PCR were used to perform MSI detection on tissue samples.Results Among the 135 patients,125 had normal mismatch repair function(pMMR)and 10 had missing mismatch repair function(dMMR).Compared with pMMR patients,dMMR patients had a larger tumor volume,were more likely to occur in the right half of the colon,and were more prone to mucinous adenocarcinoma or poorly differentiated cancer.Among dMMR patients,4 cases showed PMS2 deficiency and 3 cases showed patchy PMS2 expression.PCR detection revealed that 8 patients belonged to the highly unstable microsatellite group(MSI-H),1 patient belonged to the low instability microsatellite group(MSI-L),and 1 patient belonged to the stable microsatellite group(MSS).Among patients with PMS2 deficiency or weak expression,62.5%(5/8)were MSI-H.The Kappa value of the consistency analysis between IHC and PCR detection results was 0.943,with P<0.001.Conclusions IHC and PCR have high consistency and reliability in diagnosing MSI status in colorectal cancer patients.However,when IHC testing is negative or weakly positive,it is recommended to perform PCR testing to avoid missed diagnosis.The comprehensive application of these two methods can help improve the accuracy of MSI detection in colorectal cancer patients.