Analysis of Breast Cancer Cells/Blood When a Treatment Loses Its Effectiveness

Breast cancer (mammary carcinoma) is a malignant disease of the breast gland tissue characterized by uncontrolled cell proliferation in the breast gland. The cancer cells possess certain characteristics, such as structures on their surface—including hormone receptors or the HER2 receptor—that can be targeted by drug therapy. If no hormone receptors or HER2 receptors are detectable, the cancer is referred to as triple-negative breast cancer. However, there are situations in which a therapy that should work does not take effect or loses its effectiveness over time. This may be because tumor cells either possess additional characteristics from the outset that make them resistant to a drug, or because they develop this resistance only during the course of treatment. In both cases, this means that the drug is no longer effective, either from the start or after a certain period of time. The exact mechanisms leading to the development of such resistance are not yet fully understood.

The REMERGE study aims to investigate the mechanisms behind the development of such resistance. To this end, tissue and blood samples will be collected from patients who have experienced tumor regrowth or developed new tumor lesions while undergoing ongoing cancer therapy, or who clearly do not respond to therapy within 4 weeks of starting treatment. These samples will be analyzed in detail using various diagnostic methods to gain insights into the resistance mechanisms that may contribute to the development of new cancer therapies.

Women and men aged 18 and older who have breast cancer are eligible to participate in the study. Patients with triple-negative or HER2-positive and/or hormone receptor-positive breast cancer will be enrolled in the study. At the time of the new tumor growth or the new lesion, the patient must have been receiving cancer treatment for at least six months, to which the cancer is now resistant. Otherwise, it must become apparent within 4 weeks of starting treatment that the therapy is not effective (primary resistance). Patients must be willing to undergo a tissue biopsy and a blood draw. No new drug is being investigated in this study.