MUC4 and COVID-19: By using the same approach, we also showed that age and mRNA expression of MUC1, MUC2, MUC4, MUC6, MUC13, MUC16, and MUC20 were the most accurate variables associated with the presence of COVID-19 among symptomatic patients (Figure 5B and Supplemental Table 2; AUCROC = 91.8%; sensitivity: 90.6%; specificity: 93.3%).