Immunohistochemical HER2 expression not associated with clinicopathological characteristics of stage I-III gastric cancer patients.

Background/aims: The aim of this study was to investigate the association of human epidermal growth factor receptor 2 (HER2) expression with clinicopathological characteristics of resectable gastric cancer patients.

Methodology: A total of 394 stage I-III surgical gastric cancer patients who were detected of immunohistochemical (IHC) HER2 expression postoperatively were included in this retrospective study. Association of IHC HER2 over-expression (3+) rate with clinicopathological characteristics was tested by univariate and multivariate analyses.

Results: IHC HER2 over-expression rate was 5.1% (95% CI 3.1%-7.7%). By univariate analyses, none of the clinicopathological characteristics was associated with the IHC HER2 over-expression compared to negative expression (0/1+) (p>0.05), with the exception of a higher rate (12.2%) of IHC HER2 (3+) in moderate differentiation subset (p=0.02). However, the multivariate analyses didn’t selected any characteristic as an independent risk factor of IHC HER2 over-expression or the combination of IHC HER2 (2/3+).

Conclusions: IHC HER2 over-expression rate is relatively low among stage I-III gastric cancer patients, and might be generally not associated with clinicopathological characteristics.