Comparison of HER-2 Amplification with Clinicopathological and Prognostic Parameters in Metastatic Gastric Carcinomas

Abstract

Introduction: HER2 overexpression is present in 7 to 34% of gastric carcinomas. Several studies have demonstrated associations between HER2 overexpression and clinicopathological variables, including tumor depth, lymph node metastasis, and intestinal morphology. HER2 overexpression has been linked to shorter survival.

Aim: In this study, we aimed to determine the frequency of HER2 overexpression in patients with metastatic gastric carcinoma referred to our clinic, to assess HER2 expression using immunohistochemistry (IHC) or silver in situ hybridization (SISH) and to demonstrate potential associations between HER2 expression and histopathological parameters.

Materials and Methods: In this study, we assessed archival samples from 120 patients diagnosed with metastatic gastric carcinoma between 2015 and 2019 and tested for HER2 status. Samples had been obtained by endoscopic biopsy in 84 patients and gastric resection in 36 patients, whereas 36 patients were diagnosed in other health facilities and were referred to our department for consulting. Hematoxylin-eosin stained preparations were reassessed, and diagnoses were confirmed based on World Health Organization (WHO), and Lauren classifications and HER2 results were compared to previous results.

HER2 status was assessed by immunohistochemistry (IHC) or silver in situ hybridization (SISH) in available paraffin-embedded tumor sections. Associations between HER2 expression levels and age, sex, tumor location,  size and histological type of the tumor, lymphovascular,  perineural and perinodal invasion and perinodal invasion, lymph node metastasis, and site of metastasis.

Results: 84 (70%) out of 120 patients with metastatic gastric carcinoma were male, and 36  (30%) were female, and the mean age was  60.7 years  (age range: 21-90 years).  84 patients had undergone an endoscopic biopsy, and 36 patients had undergone gastric resection, whereas 39 patients were diagnosed in other health facilities and were referred to our department for consulting.

In total 31(25.8%) out of 120 subjects tested positive for HER2 overexpression

Comparisons of histological patterns, according to Lauren's classification, indicated that intestinal type was predominant in both groups, and none of the diffuse gastric carcinomas was HER2 positive. A statistically significant intergroup difference was found with respect to the prevalence of diffuse gastric carcinoma (p=0.03).

Conclusion: In our study, HER-2 gene amplification (25.8%) is compatible with the literature. Her2 positive tumors were mostly located proximally and were not observed in diffuse type. In this respect, they were found statistically significant.

Keywords:Her2,SISH,Gastric  Carcinoma

Original Article:

DOI: 10.7176/JHMN/79-07

Publication date:August 31^st 2020