HER2 Amplification, Polysomy17 and Histopathological Features in Pakistani Breast Cancers

Breast cancer is one of the most common cancers occurring among women throughout the world, and is the leading cause of death from cancer. Globally, it averages more than 1.1 million new cases, where developed countries face 55% of the burden; the incidence is rapidly catching up in the developing world as well (Parkin et al., 2005). In Pakistan like other Asian countries, breast cancer among females is frequently reported at an advanced stage, which is most likely due to lack of awareness and early screening programs (Ahmad, 1991; Naeem et al., 2008). Being a heterogeneous disease, breast cancer is characterized by multiple subtypes as revealed by differential gene expression profiles. Its diverse nature points towards the involvement of multiple prognostic and predictive tumor markers (Turaga et al., 2010). Epidermal growth receptor 2, commonly known as HER2 is a crucial breast cancer oncogene, which is located on the long arm of chromosome 17 and encodes a 185-KDa cell surface receptor with tyrosine kinase activity (Akiyama et al., 1986; Slamon et al., 1989). Although, early studies have