Higher baseline levels in ILD patients than controls, in patients with FVC lower than 50% and in progressor than stable patients but no prediction of progression based on baseline KL-6 levelsPrediction of progression by increased levels of KL-6 with a sensitivity of 86.4% and a specificity of 41.7%Increased levels of KL-6 are an independent risk factor for progression. This evidence concerns the gene MUC1 and interstitial lung disease.