HER2/HER3 heterodimers are reported to be activated in pancreatic cancer [31], the fact that anti-HER3 monoclonal antibody (3D4) and anti-HER2 monoclonal antibody (trastuzumab) synergetic down-regulated pHER3 in the AsPC-1 cell indirectly proved the simultaneous inactivation of HER2/HER3 heterodimers. The gene discussed is ERBB3; the disease is familial pancreatic carcinoma.