青年大肠癌微卫星不稳定和hMLH1/hMSH2表达缺失在遗传性非息肉病性大肠癌初筛中的应用

Microsatellite analysis and hMLH1/hMSH2 expression detection in young patients with colorectal cancer: value in screening hereditary nonpolyposis colorectal cancer

目的探讨青年大肠癌中微卫星不稳定发生率和hMLH1/hMSH2表达缺失率及其在遗传性非息肉病性大肠癌初步筛查中的作用。方法对73例中国南方青年大肠癌患者(年龄≤40岁)进行微卫星不稳定和hMLH1/hMSH2蛋白免疫组化检测。结果微卫星不稳定性发生率为56.16%,hMLH1和/或hMSH2表达缺失率为49.32%,二者皆随患者发病年龄的降低而迅速增加;二者对阳性病例的检出率相似。结论中国人青年大肠癌DNA错配修复基因缺陷为频发事件,运用微卫星不稳定分析和hMLH1/hMSH2蛋白免疫组化检测可在青年大肠癌有效地进行HNPCC患者及家系的初步筛查。

Objective To evaluate the frequency of microsatellite instability （MSI） and absence of hMLH1/hMSH2 expression in young patients with colorectal cancer, and investigate their role in screening hereditary nonpolyposis colorectal cancer （HNPCC）. Method Seventy-three young patients （below 40 years old） with colorectal cancer were examined for DNA mismatch repair deficiency by microsatellitte testing and imunohistochemical detection of hMLH1/hMSH2 gene products. Results The frequency of MSI and absence rate of hMLH1/hMSH2 expression are 56.16% and 49.32% in these patients, respectively, which increased significantly with younger age for cancer diagnosis. Conclusion Defects in the DNA mismatch repair system are frequent in Chinese young patients with colorectal cancer. Microsatellite analysis and imunohistochemical detection are useful for efficient identification of HNPCC in these young patients.