Breast cancer ErbB2 status in Asian women: A review of local literature

Abstract

e22164 Background: Breast cancer incidence is increasing throughout Asia. However, the characteristics of Asian breast cancer are not always well understood due to the limited availability of local data and their inadequate inclusion in global literature databases. Effective breast cancer treatment in this region requires a better understanding of Asian breast cancer biology, including ErbB2 status. Methods: We performed a literature search in seven Asian countries on breast cancer studies in which tumour ErbB2 overexpression was assessed. The keywords erbB2 OR HER2 OR ErbB-2 OR HER-2 AND breast cancer AND (country) were used to search PubMed, international and local conference abstracts and local-language journals from the year 2000 onwards. Where available, we selected up to five representative studies from each country on the basis of population size, multi-institution patient populations, institution reputation and journal impact factor. We excluded studies containing only mRNA, serum, or cell line data or those conducted on biased populations or in western countries on Asian populations. Results: ErbB2 data from 26 Asian breast cancer studies are summarized in the table . The mean or median age of the study populations ranged from 46–56 years, with one exception. In most studies that evaluated tumour ErbB2 and hormone status, ErbB2 over-expression correlated negatively with ER positivity. Conclusions: The larger studies in particular confirm that the proportion of ErbB2-positive breast cancer in Asia is generally similar to the 20–30% reported for western women. Definitions of ErbB2 positivity using IHC vary between institutions and FISH is not routinely performed in several Asian countries. This may contribute to the fact that reliable, representative data on breast tumour ErbB2 status is scarce in Malaysia, the Philippines, India and Thailand. The increased availability of accurate ErbB2 testing and data would aid improved treatment of ErbB2-positive breast cancer in these countries. [Table: see text] [Table: see text]