The study by Oshimo et al. of 77 patients with IPF reported that baseline blood KL-6 level was an independent risk factor of AE (HR: 1.001, 95% CI: 1.000–1.001, p = 0.010), and the best cut-off level was 1300 U/mL [24]. Here, MUC1 is linked to idiopathic pulmonary fibrosis.