Validated biomarkers: The key to precision treatment in patients with breast cancer
The Breast
Duffy MJ et al
Recent DNA sequencing and gene expression studies have shown that at a
molecular level, almost every case of breast cancer is unique and
different from other breast cancers. For optimum management therefore,
every patient should receive treatment that is guided by the molecular
composition of their tumor, i.e., precision treatment. While such a
scenario is still some distance into the future, biomarkers are
beginning to play an important role in preparing the way for precision
treatment. In particular, biomarkers are increasingly being used for
predicting patient outcome and informing as to the most appropriate type
of systemic therapy to be administered. Mandatory biomarkers for every
newly diagnosed case of breast cancer are estrogen receptors and
progesterone receptors in selecting patients for endocrine treatment and
HER2 for identifying patients likely to benefit from anti-HER2 therapy.
Amongst the best validated prognostic biomarker tests are uPA/PAI-1,
MammaPrint and Oncotype DX. Although currently, there are no biomarkers
available for predicting response to specific forms of chemotherapy,
uPA/PAI-1 and Oncotype DX can aid the identification of lymph
node-negative patients that are most likely to benefit from adjuvant
chemotherapy, in general. In order to accelerate progress towards
precision treatment for women with breast cancer, we need additional
predictive biomarkers, especially for enhancing the positive predictive
value for endocrine and anti-HER2 therapies, as well as biomarkers for
predicting response to specific forms of chemotherapy. The ultimate
biomarker test for achieving the goal of precision treatment for
patients with breast cancer will likely require a combination of gene
sequencing and transcriptomic analysis of every patient's tumor.
