EGFR and lung adenocarcinoma: Sixty-one (45.8%) of the 133 cases showed EGFR expression levels corresponding to 3+, 30 (22.6%) cases showed EGFR levels of 2+, and 23 (17.3%) cases showed EGFR levels of 1+; the remaining 19 (14.3%) cases showed level 0 staining (n = 133 lung adenocarcinoma samples).