A phase II study prospectively evaluated EGFR mutant NSCLC patients treated with erlotinib or gefitinib and noted that 83% achieved a PR and 11% SD without a statistically significant difference in progression-free survival (PFS) (6.6 months) or overall survival (OS) (15.9) between the two TKIs (35). Here, EGFR is linked to non-small cell lung carcinoma.