Drug screening of tumor cell lines and patient-derived xenografts showed subtype-dependent response profiles, showing a response to EGFR and HER2 inhibitors in the CMS2 epithelial/canonical group, and high sensitivity to heat shock protein 90 inhibitors in cells pertaining to the CMS1 microsatellite instability/immune and CMS4 mesenchymal groups [256]. The gene discussed is EGFR; the disease is neoplasm.