Furthermore, considering that these cell lines are EGFR-positive TKI-resistant NSCLC cells, a synergistic effect of gefitinib and siRNA may be regarded as proof of restored sensitivity of EGFR-positive NSCLC to gefitinib as a result of silencing the expression of resistance-related genes [71]. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.