HER-2 OVER-EXPRESSION IN GASTRIC CARCINOMAS IN LAGOS: A 5 YEAR RETROSPECTIVE STUDY

Abstract

Background/Introduction: Gastric carcinoma is the second most common digestive tract
cancer and the third leading cause of cancer-related death worldwide. In Nigeria, it is a major
contributor to cancer-related mortality. There is a recent interest in studying the benefits of
targeted therapy in its management using anti-HER-2 monoclonal antibody because of the
increased overall survival when used in combination with chemotherapy.
Aim and Objectives: The objective of this study was to determine the frequency of HER-2
over-expression in gastric carcinomas in Lagos, comparing it with known pathologic and
prognostic factors and also with similar available studies.
Materials and Methods: The clinical data were retrieved from two laboratories in Lagos
(Lagos University Teaching Hospital and The Specialist Laboratories) involved in the study.
Haematoxylin & Eosin slides were made from the patients’ formalin fixed paraffin embedded
blocks and were reviewed to confirm diagnosis and pathological parameters. HER-2 over
expression was assessed by staining with anti-HER-2 antibody. The data was analysed using
SPSS 16 to correlate HER-2 over-expression and the pathological features of the carcinomas.
Results: Of the 54 cases, 42 were biopsies and 12 were gastrectomies. The mean age was
55.96 years. The male to female ratio was 3.2:1. Majority of the carcinomas were of intestinal
type (83.3%), with diffuse, mixed and indeterminate types accounting for 13%, 1.9% and
1.9% respectively. Almost half of the cases (44%) were of the moderately differentiated
grade and patients who had gastrectomies presented mostly with stage T3 disease (75%).
HER-2 was over-expressed in 13% of cases, with one equivocal case. There were no
statistically significant associations between the variables tested (histotype, grade, stage),
although most cases over-expressing HER-2 were of the intestinal type.
Conclusion: HER-2 over-expression occurs in a small percentage of gastric carcinomas in
Lagos and is independent of most of the pathological parameters, although most of the cases
with HER-2 over-expression are of the intestinal histotype. Further work, with larger cohort,
is needed to better characterize the possible prognostic benefits of targeted anti-HER-2
therapy in gastric carcinomas.