Abstract

OBJECTIVE

Human epidermal growth factor receptor 2 (HER2) is a member of the epidermal growth factor receptor family, having tyrosine kinase activity. Amplification of this receptor initiates some signaling pathways leading to cell proliferation and carcinogenesis. Amplification of HER2 is especially searched in breast cancers and gastric/gastroesophageal cancers.

METHODS

With the introduction of targeting therapies for HER2 has dramatically influenced the outcome of patients with HER2 positive cancers.

RESULTS

Currently HER2 testing is realised by different methods and it is crucial to standardize testing techniques to evaluate HER2 status accurately.

CONCLUSION

However there are still several controversial aspects of HER2 testing in both breast and in gastric cancers, despite decades of experience. The aim of this review is to discuss the important pitfalls and clues for HER2 assessment.