Breast
Distinct Molecular Mechanisms Predicting Tumor Malignancy at Early Stage in Different Subtypes of Breast Cancer
By FOSTER CITY, CA, U.S.A
Apr 22, 2005, 07:14

Scientists from a joint research study conducted by Applied Biosystems Group (NYSE:ABI), an Applera Corporation business, and the Norwegian Radium Hospital will today report the discovery of a new set of potential prognostic biomarkers for early stage breast cancer at the Human Genome Organization (HUGO) 10th Annual Human Genome Meeting in Kyoto, Japan.

Using Applied Biosystems Expression Array System and Human Genome Survey Microarray, researchers identified a set of 54 genes with the greatest prognostic value for breast cancer and discovered that tumor aggressiveness may be determined at early stage in different subtypes of breast cancer. Findings suggest that these subtypes of breast cancer represent biologically distinct diseases and substantiate the value of gene expression-based subtypes in the prognosis and diagnosis of breast cancer at an early stage.

�Breast cancer is a complex disease and its biology remains a challenge to understand,� said Anne-Lise B�rresen-Dale, Ph.D., Head of the Department of Genetics, Norwegian Radium Hospital. �While traditional prognosis factors, such as metastasis, lymph nodes and tumor size, provide limited information about the underlying biology of the disease, Applied Biosystems Expression Array System has allowed us to further and systematically characterize the two breast cancer subtypes at the molecular level as well as to identify novel biomarkers.�

Researchers identified 1,210 marker genes from samples of early stage breast tumors and characterized them into two previously defined subtypes of breast tumors, Luminal A, signifying an optimistic prognosis, and Basal, signifying a worse prognosis. Of the 1,210 genes, 54 were identified that best discriminate between the two breast cancer subtypes and were validated using TaqMan� Gene Expression assays as potential prognostic biomarkers.

Further analysis of the 1,210 genes using the PANTHER� Protein Classification System for functional classification and pathway analysis revealed different molecular mechanisms predicting tumor aggressiveness that may be preprogrammed at early stage breast cancer.

�Using the highly sensitive Expression Array System together with tools such as the PANTHER� Protein Classification System and TaqMan� Gene Expression Assays provides researchers with a comprehensive approach to begin to decipher the molecular basis of disease,� said Catherine M. Burzik, President of Applied Biosystems. �The results from this study provide further evidence that gene expression-based biomarkers may be useful in both the diagnosis and prognosis of early stage breast cancer, as well as in the identification of drug targets for more targeted breast cancer therapeutics.�

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