Our aim is to improve the understanding of treatment effects, ranging from those of current clinical drugs to immune system-based, on breast cancer tumors, in particular, their interaction with tumor heterogeneity. In particular, A1 Develop spatial transcriptomics (ST) technique targeting T-cell receptors (TCRs) called TCR-ST. A2 Further immuno-oncology by developing a system for assessment of killing efficiency of T-cells, effectively turning T-cells into a therapeutic option in the context of organoids. A3 Apply a multi-omics strategy, including ST, TCR-ST, and single-cell sequencing, to a well-developed clinical system for breast cancer, spanning from fine-needle samples over primary tumors samples to organoids, which will be exploited for therapy response evaluation. We do computer science.