Breast cancer is a very complex disease. There are four subtypes of breast cancer, for which specific therapies are dedicated. The future of oncology is the so-called targeted therapies, which modify the molecular mechanism that is crucial for the progression of the tumour cell. Unfortunately, some patients do not respond to such treatments, and others develop resistance to the drugs used over time. We now know that the classical subtypes of breast cancer are intrinsically heterogeneous, which may explain the different response of patients to a given drug. Therefore, one of the greatest challenges of molecular oncology and biotechnology is to identify the mechanisms of resistance to targeted therapies and to search for new drug targets. The research is conducted by a team led by Rafał Sądej, PhD, Assistant Professor at the Department of Molecular Enzymology and Oncology of the Intercollegiate Faculty of Biotechnology at the University of Gdańsk and Medical University of Gdańsk.