Measuring gene expression may provide more accurate information for certain breast cancers than classification based on laboratory examination of tumor tissue, or histologic grade, alone, according to a new study published in the Journal of the National Cancer Institute.

Thirty to sixty percent of all breast cancer tumors are typed as histologic grade 2, with an intermediate rate of recurrence. However, this information does not help doctors make better clinical decisions about the type of therapy a patient should receive.

Christos Sotiriou, M.D., Ph.D., of the Jules Bordet Institute in Brussels, Belgium, and colleagues examined microarray data from 189 invasive breast cancers and three published sets of gene expression data in breast cancers to determine if gene expression profiling might help doctors make clinical decisions more accurately than histologic grade. The researchers identified a 97-gene expression score associated with the tissue grade of the tumor. A high expression score meant the patient was at higher risk of breast cancer recurrence, whereas a low score meant a patient had a lower risk of breast cancer recurrence.

Gene expression profiling may improve the accuracy of tumor grading and thus its prognostic value, the authors conclude.

SOURCE:
Journal of the National Cancer Institute, February 15, 2006