Comparison of the influence of human epidermal growth factor receptor 2/neu on the markers of aggression in gastric adenocarcinomas and ductal carcinoma breast

Abstract

Background: Human epidermal growth factor receptor 2/neu (HER2/neu) assessment is carried out in gastric adenocarcinomas (GAC) and invasive ductal carcinoma (IDC) breast to decide upon of trastuzumab targeted therapy. The study the only of its kind which has compared the influence of HER2/neu expression to markers of tumor aggression in these two malignancies in similar target population. Material and Methods: HER2/neu evaluation was conducted by immunohistochemistry (IHC) using the guidelines of Trastuzumab for Gastric Cancer trial for GAC and ASCO-CAP 2013 for IDC breast. The study correlated HER2/neu expression with markers of tumor aggression. Aims: The present retrospective study compares the disease influence of HER2/neu over expression on markers of disease aggression like age at presentation, grade of tumor and lymph node metastasis in GAC and IDC. Results: We have compared 82 cases of GAC with 113 cases of IDC. HER2/neu expression was seen in 23.2% and 36.3% of GACs and IDCs respectively. The mean age of HER2/neu positive GACs was found to be 3.47 years greater than their negative counterpart but the pattern was reversed in cases of IDC breast where the mean age of HER2/neu positive tumors was 6.09 years less than their negative counterpart. Though no correlation was found between grade of tumor and HER2neu status in GACs (P = 0.2930), however in IDC breast a significant correlation HER2neu positivity was found with higher grade (P = 0.0002). Similarly though we did not find any correlation of HER2neu status with nodal metastasis in GACs (P 0.0511) but in IDCs a significant correlation was found of nodal metastasis with HER2/neu positivity (P = 0.0001). Conclusion: We conclude that HER2/neu expression is more frequent in IDC breast and is significantly associated with markers of aggression in contrast to its influence on the same markers in GACs.