Fibrillar Human Serum Albumin Suppresses Breast Cancer Cell Growth and Metastasis

1.1 Breast cancer classification Breast cancer is one of the most common cancers among women worldwide and approximately one-third of women diagnosed will eventually develop metastases and die (Jemal et al, 2010). Breast cancer is heterogeneous at the molecular, histopathologic and clinical levels and is commonly classified into several categories according to multiple schemes, each based on different criteria. A typical description of breast cancer can be comprised of tumor grade, histologic type, tumor stage, and the expression of proteins and genes etc. (McSherry et al, 2007). Normal non-cancerous cells are differentiated and have specific cell shapes and functions; whereas, cancer cells lose differentiation (dedifferentiate), have less uniform nuclei, and exhibit uncontrolled cell division. Pathologists, therefore, determine breast cancer by grade according to the degree of differentiation of cells compared to normal breast cells: highly differentiated (low grade), moderately differentiated (intermediate grade), and poorly differentiated (high grade). Cancers classified as high grade generally have a worse prognosis (McSherry et al, 2007). The majority of breast cancers are derived from the epithelium lining the ducts or lobules of the breast. They can be classified histologically according to characteristics seen upon light microscopy of biopsy specimens. Histologic classification is divided into: ductal carcinoma in situ (DCIS), invasive ductal carcinoma, and invasive lobular carcinoma (McSherry et al, 2007). Breast cancer can further be classified using the TMN Classification of Malignant Tumors, TMN stage is based on tumor size, lymph node micrometastasis, and macrometastasis, where ‘T’ describes tumor size; ‘N’ indicates whether or not the tumor has spread to the lymph nodes; and ‘M’ indicates whether or not distant metastasis has occurred. Larger tumor size with lymph nodal spread and distal metastasis has a worse prognosis (Gonzalez-Angulo et al, 2007). Expression of certain proteins and genes can also be used to classify breast cancer (McGrogan et al, 2008; Stickeler et al, 2009). Whole-genome analysis using expression microarray and immunohistochemical analysis has revolutionized the understanding of breast carcinomas in recent years, and led to the discovery of five distinct subtypes of breast carcinomas (luminal A, luminal B, HER-2 overexpression, basallike, and normal-like), each with unique recognizable phenotypes and clinical outcomes (McGrogan et al, 2008; Stickeler et al, 2009). By using classification to characterize each cancer patient, it may help select the suitable treatment strategies to achieve an optimal outcome and increase therapeutic efficacy.