Recently, Choi et al. reported that the relative change in mucin-1/KL-6 levels at 1 month predicted disease progression (defined as relative decline in FVC ≥ 10% or DLco ≥ 15%, or AE-IPF, or deaths) over 6 months after antifibrotic treatment [42]. Here, MUC1 is linked to idiopathic pulmonary fibrosis.