The question arises whether there still is a role for E1A expression in the pathogenesis of COPD as proposed by Hogg et al. From theirs and an other study [24] it follows that E1A DNA and E1A protein is more abundantly expressed in epithelial cells from COPD patients, though the reason for increased E1A expression in COPD patients remains elusive. Here, DHTKD1 is linked to chronic obstructive pulmonary disease.