CCNE2 and lung cancer: In recent years, a variety of biomarkers have been reported which are associated with OS of lung cancer, such as S100A4 (15), lymphocyte to C-reactive protein ratio (16), mini-chromosome maintenance complex component 7 (MCM7), and cyclin E2 (CCNE2) (17), LY6/PLAUR domain containing 3 (LYPD3) (18).