We found increased BRCA1 expression with GOLD I/II COPD (3.58-fold, P = 0.0001) and GOLD III/IV COPD (1.79-fold, P = 0.04) (Figure 7B), although we also identified a significant decrease in BRCA1 mRNA expression between GOLD I/II and GOLD III/IV disease (0.60-fold, P = 0.01). Here, BRCA1 is linked to chronic obstructive pulmonary disease.