[Immunohistochemical assessment of HER2 expression in gastric cancer. A clinicopathologic study of 93 cases].

Background: Gastric cancer in Mexico is ranked third in both males and females. Most patients present clinically with advanced disease and treatment options are sparse. HER2 overexpression in gastric cancer is related to poor outcome. Immunohistochemical testing for HER2 is becoming the standard of care for guiding adjuvant treatment of gastric cancer with trastuzumab.

Objectives: To determine the frequency of HER2 overexpression in patients with gastric cancer in the Hospital de Oncología del Centro Médico Nacional, Siglo XXI and its association with other histopathological findings.

Material And Methods: Patients with gastric cancer who underwent surgery between March 12, 2006-August 31, 2011, were enrolled in this retrospective study. Diagnosis was confirmed by review of slides and immunohistochemistry with anti-HER2 antibody was performed. Scoring was done by Hoffman scoring system. Medical records were evaluated.

Results: Ninety-three patients were included in the study, with 43 (46.2%) male and 50 (53.7%) female patients. The median age was 64 years. HER2-positive tumours were identified in 6 patients (6.45%) and located most frequently in the proximal stomach. There was no difference in HER2 overexpression in relation to age, gender or histologic type.

Conclusion: In our study, about 7% of patients with gastric cancer were HER2-positive on immunohistochemistry.