Fig. 4

Mean values and standard deviation (relative expression) of SIRT-1 (a), HDAC2 (b), and DNA methylation levels (c) in tumor (T) and non-tumor (NT) lungs of LC and LC-COPD patients. Definition of abbreviations: miR, microRNA; SIRT-1, sirtuin-1; and HDAC2, histone deacetylase 2. Statistical significance: ^#p < 0.05, ^###p < 0.001 between non-tumor specimens of LC-COPD and non-tumor lungs of LC patients; ^§§§p < 0.001 between tumor lungs of LC-COPD and tumor specimens of LC patients; and n.s., non-significant differences between the study groups