B2M and neoplasm: To summarize, downregulation of the drug target, cell dormancy, and upregulation of the IGFBP7, MDK, and B2M that were common characteristics of tumor cells in patient basal tumor cluster #3 and PDX cluster B could contribute to therapeutic resistance to tipifarnib, indicating a selection for intrinsically resistant basal tumor cluster #3 subpopulations in BC159-T#3.