MUC1 and systemic sclerosis: Several biomarkers have been investigated as predictors for the development or outcomes of SSc-ILD, including cytokines (e.g., IL-6), chemokine ligands (CCL18, CCL2, CXCL4), matrix enzymes (matrix metalloproteinases 7 and 12), secretory products of pneumocytes (KL-6), and anti-Ro52 [10, 19–25]; however, none is widely available, perhaps with the exception of KL-6, which has been approved for clinical use in Japan.