Non-Genetic Heterogeneity and Immune Subtyping in Breast Cancer: Implications for Immunotherapy and Targeted Therapeutics

•Non-genetic factors shape cancer evolution and influence therapeutic outcomes.•Non-genetic heterogeneity diverse subpopulations of cancer cells within breast tumors, can arise through clonal evolution, genetic changes, epigenetic changes, and reversible phenotypic transitions.•Intratumoral heterogeneity revealed by immunological microenvironment has opened novel opportunities for immunotherapy research.•This review focus on adaptive methods; alterations in drug targets, immune system evasion, activation of survival pathways, and alterations in metabolism.