Clinical significance of immunohistochemistry and fluorescence in situ hybridization for detection of human epidermal growth factor receptor 2

LI Huiming; XU Fanghua; YUAN Min; ZHANG Zhiqin

Abstract：Objective:To investigate the relationship between human epidermal growth factor receptor 2(HER2)gene status distribution,HER2 gene amplification/HER2 protein expression and clinicopathological features in colorec-tal cancer according to the differentstandard for evaluation.Methods:Paraffin tissue samples of 100 patients undergoing radical resection of colorectal cancer in PingXiang people's Hospital from January 2019 to December 2021 were collect-ed,and the clinical and pathological information of patients were collected.Automatic immunohistochemistry(IHC)was used to detect HER2 protein and fluorescence in situ hybridization(FISH)was used to detect HER2 gene expres-sion in all cases,and its relationship with clinicopathological features was analyzed.Results:In 100 patients with color-ectal cancer group,the positive expression rates of HER2 protein were 34％,27％and 20％under three different sco-ring criteria respectively.The difference was no statistical significant(P＞0.05).The consistency of HER2 protein ex-pression of 3+,2+,1+,0+and gene amplification under IHC scoring criterion 1 was 50.0％,12.5％,2.6％,0,re-spectively.The consistency of HER2 protein expression and gene amplification under IHC score 2 was 71.4％,15.0％,2.9％,0,respectively;the consistency of HER2 protein expression and gene amplification under IHC score 3 was 100.0％,20.0％,2.9％,0,respectively.The consistency of HER2 protein and gene amplification was the highest under IHC sco-ring criterion 3.HER2 gene amplification was detected by FISH in 9 cases(9.0％).HER2 gene amplification was not correlated with age,sex,pathologic stage,and depth of invasion(P＞0.05),but was correlated with differentiation de-gree and lymph node metastasis(P＜0.05).Conclusion:There was no statistical difference in the positive rate of HER2 protein expression among the three scoring criteria,but the consistency of HER2 protein expression and gene amplifica-tion was the highest under scoring criteria 3.The amplification of HER2 gene was related to the degree of differentia-tion and lymph node metastasis.Scoring criterion 3 should be preferred for the detection of HER2 protein expression in clinic.