Figure 2
Statistical significance of genes up-regulated in the left airway epithelium compared with the airway epithelium of 20 healthy non-smokers and smokers in whom the right airway epithelium was sampled 1st. The P values of the 267 genes that were up-regulated >2-fold in the left airway epithelium (sampled 2nd) compared with the right airway epithelium (sampled 1st) were calculated using the two-tailed Student f-test, assuming equal variances. Shown on the ordinate is the P value for each gene and on the abscissa, arbitrary gene number from 1 to 267, derived from the alphabetical order of the GenBank or TIGR identifiers, left to right. Note that 23 genes had a P value < 0.01 (â–˛), while the remainder had a P value > 0.01 (â–ł).