On the other hand, serum KL-6 levels were significantly higher in SSc patients who developed SSc-ILD during the follow-up period compared with those who did not (480.0 ± 149.5 pg/mL vs. 264.7 ± 98.04 pg/mL, p = 0.0011). The gene discussed is MUC1; the disease is systemic sclerosis.