Nevertheless, several uncertainties remain regarding EGFR, including: (1) the prevalence of this mutation among all patients with NSCLC; (2) the need for a second biopsy, given that testing for EGFR requires volumes of tumor that are often beyond that obtained for diagnosis; and (3) the optimal EGFR testing strategy (i.e., test all patients or confine testing to patients with correlated clinical characteristics.  Those issues may strongly influence the effectiveness and cost-effectiveness of EGFR testing as a management strategy for patients with NSCLC. Here, EGFR is linked to neoplasm.