Breast cancer biomarkers

Due to the discovery of specific prognostic and predictive bio-markers that allow the application of more individualized therapies to different molecular subgroups, breast cancer treatment has experienced several changes over the past decades.

These subgroups demonstrate specific differences in clinical biological behavior. In addition to the classic clinical prognostic factors of breast cancer, established molecular bio-markers such as estrogen receptor and progesterone receptor have played an important role in the selection of endocrine therapy patients for many years.

More recently, the human epidermal growth factor receptor 2 (HER2) has been validated as a predictor of the response to HER2 targeting therapy as well as a prognostic factor. The shift to earlier breast cancer diagnosis due to enhanced imaging methods and screening programs highlights the need for new biomarker factors and combinations to quantify patients ' residual risk and indicate the potential value of additional treatment strategies. In addition to its moderate prognostic value, the Ki67 proliferation marker has recently emerged as an important marker due to several applications in neo adjuvant therapy.

Numerous multigene signatures have been identified with the introduction of high-throughput technologies aimed at outperforming traditional markers: current prospective clinical trials are seeking evidence of their definitive role in breast cancer. There are many more factors and approaches that may become relevant in the near future, including the detection of single disseminating and circulating tumor cells in the blood and bone marrow, as well as cell-free DNA and micro RNA circulating.Careful randomized prospective testing and comparison with existing established factors will be required to select those emerging markers that offer significant cost - effective benefits and thus justify their routine use for decision - making in breast cancer therapy.