From this training program, 11 microarrays that failed QC were available from small airway epithelium samples collected from individuals with COPD (n = 1 failed due to the RIN criteria; n = 6 failed the GAPDH criteria; n = 3 failed the scaling factor criteria; and n = 1 failed both the GAPDH and scaling factor criteria). This evidence concerns the gene GAPDH and chronic obstructive pulmonary disease.