A Medical Device Daily

Scientists from a joint research study conducted by Applied Biosystems Group (Foster City, California) and the Norwegian Radium Hospital (Oslo, Norway) reported the discovery of a new set of potential prognostic biomarkers for early stage breast cancer during the Human Genome Organization’s (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 they say have the greatest prognostic value for breast cancer and discovered, they added, that tumor aggressiveness may be determined at an early stage in different subtypes of breast cancer.

Their 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, PhD, head of the department of genetics at 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, the 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 from Roche Molecular Systems (Pleasanton, California) 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 pre-programmed at early stage breast cancer, the researchers said in their Kyoto presentation.

Norwegian Radium Hospital’s Department of Genetics focuses on the molecular biology of breast and ovarian cancer, with emphasis on identification of genotypes and gene expression profiles contributing to elevated cancer risk, radiation sensitivity, tumor aggressiveness and therapy resistance.

Catherine Burzik, president of Applied Biosystems, an Applera Corp. (Norwalk, Connecticut) company, said the results from the 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.”

Results of the study were presented in both an oral and poster presentation at the HUGO meeting.