The combination of pertuzumab and trastuzumab has been reported to induce a synergistic inhibition of in vivo tumor growth in BTC due to a more complex blockade of HER2/HER3 signaling, as shown in Salvatore et al. All chemo- and immunotherapics are thoroughly explained in File S1 from the Supplementary Materials. The gene discussed is ERBB3; the disease is neoplasm.