Pathway-specific gene expression profiling of breast cancer cell lines of African American and Caucasian American origin Free

B98

Breast cancer is one of the leading causes of morbidity and mortality affecting women in the United States. While the incidence rate of breast cancer is 12% lower among African American than Caucasian American women, the mortality rate is 36% higher in African American breast cancer patients. The reasons for such a disparity are subjects of intense investigations.
 Several biological and non-biological factors have been proposed to contribute to this disparity. The direct contribution of racial and ethnic background in the disparity of breast cancer incidence and mortality has not been clearly established. Very recent studies that compared breast cancer in African American versus Caucasian American women suggest that biological differences may contribute to the early onset and aggressive phenotype of breast cancer in African American women. Accordingly, the role of two breast cancer genes, BRCA1 and BRCA2, in the observed disparity are under investigation. Additionally, other studies have shown that breast cancers triple negative for estrogen receptor, progesterone receptor, and HER2/neu are aggressive and metastatic, a characteristic phenotype of breast cancer in African American women.
 We undertook a pathway-focused microarray analysis of cell lines derived from African Americans and Caucasian Americans, to examine (1) if the cells have differentially expressed pathway-specific genes, (2) if certain pathways are predominantly active in the cells, and (3) to what extent we can use cell lines to study molecular basis of disparity in breast cancer. We selected the pathways that other previous studies had suggested to contribute towards aggressive cancer phenotype.
 We discuss our preliminary results from two cell lines of African American origin and two cell lines of Caucasian American origin with regard to their expression profiles of major genes in Apoptosis signaling, NF-kB signaling, and Estrogen Receptor (ER) signaling pathways. Further studies are planned to verify the preliminary results and to perform similar analysis of primary tumor tissues.