CD34 and lung cancer: Methylation levels of seven CpGs at PCDH7 (A), VIPR2 (B), HBP1 (C), CD34 (D), HOXA9 (E), SOX17 (F), and HOXD13 (G) were compared among six different kinds of samples: bronchial washing samples from 76 lung cancer patients (BW_cancer), 60 healthy individuals (BW_control), bronchial biopsies from 8 lung cancer patients (LC_biopsy), 42 lung tumor (LC_tumor) and matched normal tissues (LC_normal), and sputum from 12 lung cancer patients (LC_sputum).