In the clinic, we mainly use anticancer drugs based on outcomes of clinical trials that have identified the best treatment for the average breast cancer patient, not considering differential patient and tumor characteristics that define the case mixes studied. Hence, this approach serves only those patients whose outcome improves substantially with ‘the best treatment’ identified, while harming patients that do not derive benefit, or even develop metastasis or progress due to the same treatment. The focus of our research line is to unravel underlying tumor and host mechanisms that ultimately define treatment efficacy and develop tests that will guide individualized treatment decisions in the clinic and eventually improve survival. For this purpose, we use several genome-wide approaches and molecular techniques, in order to dissect the mechanisms that divide clinically well-defined cohorts of breast cancer patients into resistant and sensitive to a particular treatment. We have a close collaboration with the groups of Jos Jonkers and Jacco van Rheenen, who use genetically engineered mouse models for breast cancer, to study differential drug sensitivity in a controlled fashion. In addition, we collaborate with the group of Wilbert Zwart, focusing on molecular mechanisms underlying endocrine therapy resistance.
A second research line focuses on prognostic molecular classifiers for adjuvant systemic treatment advice in breast cancer in collaboration with the groups of Lodewyk Wessels and Rene Bernards.