EGFR and lung adenocarcinoma: The potential for insufficient diagnostic tissue available for EGFR mutation testing (2, 12) prompted a study in which either no lung adenocarcinoma patient samples were tested (all received first-line chemotherapy), a second testing scenario where half of the patients had sufficient tissue for EGFR testing, or a third scenario where half of the patients had repeat tumor biopsy for EGFR testing (although 15% still had insufficient tissue after re-biopsy).