EGFR and neoplasm: While the elevation of DR4 was detected in most tumor biopsy samples (65%; 26/40) from EGFRm NSCLC patients relapsed to treatment with first generation EGFR-TKIs, DR4 was reduced in 15% of cases (6/40) and remained unchanged in 20 of cases (8/40), among which 7 showed undetectable DR4.