Breast cancer liquid biopsy stratification

Breast cancer is the most common cancer in Austrian women. An important aspect in the clinical management of breast cancer is an estimation of prognosis and treatment strategies. Traditionally this is achieved by clinical information as well as by analysis of the primary tumor or, where applicable, one of its metastatic sites. At present, status of hormone receptors and alterations in a gene by the name HER2 are among the most important factors for surveillance and treatment decisions. However, novel sequencing technologies have provided very detailed characterizations of tumor genomes and this information can be used to improve their classification. Hence, a more robust and objective classification of tumors can be achieved by including more of these tumor-specific features. Traditionally material for analyses was obtained by tissue biopsies, an often difficult and invasive procedure. In contrast, liquid biopsies are based on a blood draw and hence minimally-invasive procedures. Blood from patients with cancer can provide information about a tumor genome, as normal and tumor cells shed part of their genome as small DNA fragments into the blood. This cell-free DNA (cfDNA) is detectable in the cell-free component of blood, which is referred to as plasma. DNA fragments from tumor cells are accordingly called circulating tumor DNA (ctDNA). Our group has extensive expertise in the analysis of cfDNA and has developed a plethora of approaches for ctDNA analysis. We developed an approach, which enables to detect simultaneously alterations from tumor cells such as copy number alterations and the expression status of genes from the analysis of peripheral blood. Our project aims at utilizing this information to improve the classification of breast cancer based on a blood test and furthermore to provide markers suitable for an improved selection of treatment strategies. In addition, we will obtain novel insights into the biology of metastatic breast cancer, so that this project will have important implications not only for patients and clinical oncologists, but also for pathologists, pharmacologists, and all basic researchers interested in cancer.