Figure 3.

Differential expression of drug-metabolizing enzymes between central and peripheral airways. (A) The relationship between the first two principle components did not indicate any distinct grouping of the data due to differences in expression between healthy lung (unfilled circles) and COPD lung (black circles). However, a separation is seen between central airways (large circles) and peripheral airways (small circles) irrespectively of health status. (B) Distribution of p-values showed a high peak for the lower values, indicating that there are more significances than expected by chance between central and peripheral airways for metabolizing enzymes and transcriptional regulators.