Previous studies have shown that the mRNA expression of S100A4 (FC = 1.43, p = 0.0071), S100A9(FC = 1.66, p = 0.0001), and S100A10 (FC = 1.63, p = 0.0003) were significantly upregulated in the severe COVID-19 subjects than mild-to-moderate subjects based on 65 COVID-19 subjects and 50 healthy controls (24) These sound evidence indicated that S100A4, S100A9, and S100A10 play a role in the inflammatory conditions in COVID-19 patients and lead the onset of serious illness. The gene discussed is S100A9; the disease is COVID-19.