PGAM5 and chronic obstructive pulmonary disease: In addition, examining PGAM5 expression in tumour cells in all the smokers (whether healthy smokers or COPD) according to the degree of emphysema severity, we found no difference in expression between those without emphysema (H score, 168 ± 51; n = 7) and those with mild emphysema (H score, 151 ± 18; n = 6).