Breast cancer biomarker systems commercially availabl
In the field of cancer research and care, the concept of precision medicine—prevention and treatment strategies that take individual variability into account—hinges on the development of valid biomarkers interrogating key aberrant pathways potentially targetable with molecular targeted or immunologic therapies 1. Although biomarkers such as prostate-specific antigen PSA , have been known and used for decades to attempt to guide prognostic and therapeutic decisions, the recent revolution in molecular biology, with the rise of high-throughput sequencing and increased molecular characterization of tumor tissue has led to an exponential increase in attempts to measure and target aberrant pathways at the molecular level. Nevertheless, there has been a large gap between multiple initial reports of biomarkers, often with diagnostic performance that cannot be reproduced in later studies, and full clinical implementation and validation of the biomarkers due to issues in study design, assay platforms, and availability of specimens for biomarker development 2 , 3. Nevertheless, with the recent emergence of highly selective molecular targeted agents and high-throughput genomic characterization technologies, robust and well-validated cancer biomarkers are increasingly needed.
Language: English German. The therapy of choice for breast cancer patients requiring adjuvant chemo- or radiotherapy is increasingly guided by the principle of weighing the individual effectiveness of the therapy against the associated side effects. This has only been made possible by the discovery and validation of modern biomarkers. In the last decades and in the last few years some biomarkers have been integrated in clinical practice and a number have been included in modern study concepts.
Multigene signatures generate crucial prognostic information particularly useful for cancer patients where clinical parameters and traditional immunohistochemical markers alone lead to equivocal prognosis. Clinicians are now provided with molecular tools that assist in the outline of adjuvant therapies, namely helping decide on the extension of adjuvant endocrine therapy or on suppressing adjuvant chemotherapy in patients were toxic effects are particularly deleterious or when this treatment is fundamentally not needed. The importance of cancer multigene prognostic signatures is well elucidated in the guidelines for adjuvant systemic therapy in early-stage breast cancer and the guidelines on disease staging that are progressively integrating gene expression assays as classification biomarkers. In addition to the predictive and prognostic value, some genetic tests provide intrinsic subtyping classification. Through to now, there is not a commercially available multigene test that makes recommendations regarding adjuvant treatment for HER-2 and triple negative breast cancers.
Breast cancer is a heterogeneous disease that develops and progresses because of alterations in genes that control cell growth, proliferation, and differentiation. Although such a scenario is still not fully realized, biomarkers are beginning to play an important role in preparing the way for precision treatment in breast cancer. In particular, biomarkers are increasingly being used to predict patient outcomes and help determine the most appropriate type of systemic therapy to be used. Reflexive testing for biomarkers in newly diagnosed cases of breast cancer includes estrogen receptor ER and progesterone receptor PR status for selecting patients who should receive endocrine treatment, and human epidermal growth factor receptor 2 HER2 status for identifying patients who are likely to benefit from anti-HER2 therapy.