Here we present a functional multi-omics method, interaction-Correlated Multi-omic Aberration Patterning or iC-MAP, which dissects intra-tumor heterogeneity and identifies in situ in real time the oncogenic consequences of multi-omics aberrations that drive proliferative/invasive tumor in individuals with poor prognosis. First, given epigenetic aberrations resulting from complex interactions between genetic susceptibility and environmental influences are the primary driving force of tumorigenesis, we applied our chromatin activity-based chemoproteomics (ChaC) method to characterize the tumor-phenotypic epiproteomes (epigenetic regulatory proteomes) in breast cancer (BC) patient tissues. A biotinylated ChaC probe UNC0965 that specifically binds to the oncogenically active histone methyltransferase G9a enabled the sorting/enrichment of a G9a-interacting epiproteome representing the predominant BC subtype in a tissue, which is separated from other cell types, especially non-malignant cells where G9a is less enzymatically active. ChaC then identified UNC0965-captured G9a interactors that are mostly involved in the oncogenic pathways associated with tumor cell viability and invasion. Using BC patient transcriptomic/genomic data we retrospectively identified the G9a interactor-encoding genes that show individualized iC-MAP in BC-subtypic patients with incurable metastatic disease, revealing essential drivers of proliferative or invasive BC phenotypes. Our iC-MAP findings can not only act as new diagnostic/prognostic markers to identify patient subsets with metastatic disease but also create precision therapeutic strategies that can match proliferative or invasive potential of individual patients.