Task: Question Answering
Input (English): Context: Mutations in the tyrosine kinase (TK) domain of the epidermal growth factor receptor (EGFR) gene in non-small cell lung cancers are associated with increased sensitivity of these cancers to drugs that inhibit EGFR kinase activity such as gefitinib and erlotinib. Responses to TK inhibitors in the absence of EGFR gene mutation for BAC patients have not been reported. A case of a patient with BAC refractory to chemotherapy who responded to gefitinib in the absence of EGFR gene mutations is reported. Tyrosine kinase inhibitors may have a role in BAC in the absence of EGFR gene mutations. Additional studies on other molecular alterations of the EGFR family members are needed to better predict response to these agents. 
 Question: Mutations in which gene determine response to both erlotinib and gefitinib?
Output (English): epidermal growth factor receptor (egfr) gene