Quest Diagnostics Inc. has introduced its newly developed test, the Breast Cancer Gene Expression Ratio, to help physicians predict the risk of disease recurrence in women with estrogen receptor-positive, lymph node-negative breast cancer. Quest Diagnostics is the first company to develop a breast cancer recurrence test based on licensed gene-expression profiling technology from AviaraDx Inc., a molecular cancer profiling company.
The Breast Cancer Gene Expression Ratio is based on the homeobox gene-B13 (HOXB13) and the interleukin-17B receptor gene (IL17BR). In breast cancers that are more likely to recur, the HOXB13 gene tends to be over-expressed, while the IL-17BR gene tends to be under-expressed. In an 852-patient retrospective study published recently in the Journal of Clinical Oncology, the HOXB13:IL17BR ratio (H:I expression ratio) independently predicted breast cancer recurrence in patients with ER-positive, lymph-node negative cancer. The H:I expression ratio was found to be predictive in patients who received tamoxifen therapy as well as in those who did not.