But these same quinones showed a much higher potency in the inhibition of breast tumor cells expressing HER2 or the trastuzumab resistant HER2 oncogenic isoform, HER2Δ16 (The IC50 of the effective compounds was measured by treating each of the cell lines with different drug concentrations for 48 h followed by the CellTiter-Glo Assay to detect cell viability). The gene discussed is ERBB2; the disease is breast neoplasm.