PTEN and chronic obstructive pulmonary disease: There was no significant association between any other classification of expression for PD-L1, FGFR1, PIK3CA, PTEN, p16 and total/local severity of emphysema, between classification of expression for PD-L1, FGFR1, PIK3CA, PTEN, p16 and presence of COPD/GOLD staging.