Comparsion Of HER2 Expression Between Primary Gastric Adenocarcimona And Regional Lymph Node Metastasis And Its Relationship With Prognosis

Objective: To evaluate the heterogeneity of HER2 protein expression in primary gastric tumours and regional lymph node metastases, and to study its prognostic significance and the association with the clinicopathologic features.Methods: The expression of HER2 was evaluated using immunohistochemistry(IHC)and assessed using the modified HercepTest scoring criterion in the primary tumour and regional lymph node metastasis of 135 gastric cancer patients. The results were compared by kappa test.The association between heterogeneity of HER2 protein expression and clinicopathological features was analyzed by chi-square test. Kaplan-Meier survival analysis,Log-rank test and Cox regression model were used for the survival analysis.Results:(1)The expression of HER2 in primary tumour as follows: HER2(3+) was found in 18.5%(25/135), HER2(2+)was found in 20.7(28/135), HER2(1+) was found in 22.2%(30/135), HER2(0)was found in 38.5%(52/135).(2)There was significant association between HER2 protein expression and age, tumor location, Laurens typing, perineural invasion, vascular invasion, TNM stage and lymph node staging;while there was no significant associated between it and gender, tumor maximum diameter and depth of invasion.(3) The expression of HER2 in regional lymph nodes as follows: HER2(3+) was found in20.7%(28/135), HER2(2+) was found in 5.2%(7/135), HER2(1+) was found in 3.0%( 4/135), HER2(0) was found in 71.1%(96/135).(4) The Kappa value of HER2 protein expression in gastric adenocarcinoma primary site and regional lymph node was 0.315(<0.4). There is a heterogeneity of HER2 protein expression in primary gastric tumours and regional lymph node metastases, especially in the case which is HER2(2+) in primary tumour.(5) There was significant association between heterogeneity of HER2 protein expression and Laurens typing, perineural invasion, TNM stage, lymph node staging, HER2 protein in primary tumour,while there was no significant associated between it and age, sex, location, vascular invasion, tumor size, depth of invasion.(6) Kaplan-Meier survival analysis showed that there was significant difference in survival rate between the positive HER2 expression and negative ones(P <0.05); Cox regression model analysis showed that positive HER2 expression is an independent prognostic factor in gastric adenocarcinoma with regional lymph node metastasis(HR=2.230,95%CI(1.265-3.932),P=0.006).(7)There was no significant difference in survival rate between homogeneity of HER2 protein expression and heterogeneity ones.Conclusion:(1) There is a heterogeneity of HER2 protein expression in primary gastric tumours and regional lymph node metastases.(2) HER2 expression in primary tumours is an independent prognostic factor in gastric adenocarcinoma with regional lymph node metastasis.(3) There was no significant difference in survival rate beween homogeneity of HER2 protein expression and heterogeneity ones.