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. 1998 Sep 29;95(20):11891–11896. doi: 10.1073/pnas.95.20.11891

Figure 6.

Figure 6

Methylation of p16 in sputum from smokers. Bisulfite modified DNA was amplified by primers specific to methylated or unmethylated alleles of the p16 gene as described. Unmethylated p16 alleles were detected in all 16 sputum samples and in DNA from normal human bronchial epithelial (NHBE) cells obtained from a never-smoker. The Calu1 cell line (positive control for p16 methylation) is completely methylated. Methylated alleles of p16 were observed in DNA from 4 cancer-free persons (lanes 3, 10, 13, and 14), 1 person diagnosed at the time of sputum induction with a SCLC (lane 2) who developed a NSCLC 2 years later, 1 smoker (lane 15) who was positive for lung cancer at the time of sputum induction, and in the positive control (Calu1). No methylation was observed in the negative control normal human bronchial epithelial cells. Samples negative for p16 methylation are shown in lanes 1, 4–9, 11–12, and 16.