ERBB2 and cancer: Given that zotatifin downregulates the protein expression of RTK oncogenic drivers (Figure 1C and Supplementary Figure S1), the anti-tumor activity of zotatifin (i.e., effect on proliferation and apoptosis) was tested in a panel of cancer cell lines that are driven by alterations in FGFR1/2 and HER2 (Figure 2A).