MUC1 and small cell lung carcinoma: ILD, interstitial lung disease; IPF, idiopathic progressive fibrosis; CTD, connective tissue disease; HP, hypersensitivity pneumonitis; NSIP, nonspecific interstitial pneumonia; BMI, body mass index; FVC, forced vital capacity; FEV1, forced expiratory volume in 1 s; TLC, total lung capacity; DLco, diffusing capacity for carbon monoxide; KL-6, Krebs von den Lungen-6; IS, immunosuppressants, LC; lung cancer, NSCLC; non-small cell lung cancer; SCLC, small cell lung cancer