The present invention discloses novel methods and uses thereof for producing molecular spatial maps of metastatic breast cancer (MBC) and ductal carcinoma in situ of the breast (DCIS). A specific list of genes are identified using single-cell RNA sequencing and single-nucleus RNA sequencing and are used for RNA visualization of MBC and DCIS tissue microenvironment. Unexpected subtypes of tumor cells are revealed, and methods for identifying molecular biomarkers for MBC in the bone and breast and DCIS are disclosed. Furthermore, methods for identifying therapeutic agents and uses thereof for treating MBC and DCIS as well as compositions thereof comprising such identified therapeutic agents are provided.