Prospective Study
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World J Gastroenterol. May 21, 2014; 20(19): 5889-5896
Published online May 21, 2014. doi: 10.3748/wjg.v20.i19.5889
Frequency of HER2/neu overexpression in adenocarcinoma of the gastrointestinal system
Sadaf Farzand, Tahir Siddique, Kanwal Saba, Mulazim Hussain Bukhari
Sadaf Farzand, Tahir Siddique, Kanwal Saba, Mulazim Hussain Bukhari, Department of Pathobiology, King Edward Medical University, Lahore 54000, Pakistan
Author contributions: Farzand S conceived the study, analyzed the data, and performed HER2/neu analysis; Siddique T retrieved clinical information, obtained a collection of tissue specimens for analysis, and participated in editing of the manuscript; Saba K did all statistical analysis and helped in calculating sample size; Bukhari MH supervised the project and conducted pathological analyses.
Correspondence to: Mulazim Hussain Bukhari, Professor, Department of Pathobiology, King Edward Medical University, Nila Gumbad, Anarkali, Lahore 54000, Pakistan. mulazim.hussain@gmail.com
Telephone: +92-42-37592696 Fax: +92-42-37592696
Received: May 7, 2013
Revised: November 12, 2013
Accepted: December 3, 2013
Published online: May 21, 2014
Abstract

AIM: To determine the frequency of HER2/neu protein overexpression in gastric (group A), small intestine (group B), and colorectal (group C) adenocarcinoma.

METHODS: A descriptive, cross-sectional study was performed on 50 cases of gastrointestinal adenocarcinoma (stomach, small intestine, and colorectal); 11 from group A, 8 from group B, and 31 from group C. The samples were grossed and processed in the pathology department, and sections were stained with HE (hematoxylin and eosin stain) for histopathological confirmation of malignancy (well-differentiated, moderately-differentiated, and poorly-differentiated). The confirmed samples were processed for immunomarker study of HER2/neu.

RESULTS: HER2/neu protein overexpression was found in 33 (66%) patients overall (P = 0.000). Out of 33 HER2/neu positive subjects, 23 (69.6%) were from group C, while the remaining 10 (30%) were from group A. None of the patients from group B had positive HER2/neu protein overexpression. No protein overexpression or membrane staining in < 10% tumor cells was observed in 17 (34%) patients, which were labeled as score “0” and considered negative for HER2/neu protein overexpression. Faint/weak staining (in ≥ 10% of tumors cells) were observed in 8 (16%) patients and given the “1+” score. Similarly 13 (26%) patients reported moderate staining (in ≥ 10% tumor cells) and were thus labeled as “2+”, and strong staining (in ≥ 10% tumors cells), labeled as “3+”, was observed in 12 (24%) patients. Out of 50 patients, 26 (52%) were suffering from grade-II malignancy, 16 (32%) from grade-I, and 8 (16%) from grade-III. There was highly significant association between tumor grades and HER2/neu protein overexpression (P = 0.0000).

CONCLUSION: HER2/neu protein is credibly overexpressed in colon and gastric adenocarcinomas in immunohistochemistry. There is significant association between grade of tumor and HER2/neu protein overexpression.

Keywords: HER2/neu, Immunohistochemistry, Adenocarcinoma, Gastrointestinal system

Core tip: The role of HER2/neu was seen in 50 cases of gastrointestinal adenocarcinoma by immunohistochemistry. Overall, HER2/neu protein overexpression was found in 33 (66%) patients (P = 0.000), with 23 (69.6%) being colorectal carcinoma while the remaining 10 (30%) were gastric carcinoma. There was highly significant association between tumor grades and HER2/neu protein overexpression. HER2/neu protein was overexpressed in those adenocarcinomas showing a significant association between grade of tumor and HER2/neu protein overexpression. This discovery may improve treatment options for cases of gastric and colorectal carcinomas.