PYCR1 and asthma: The AUCs of proline, PYCR1, and the combination of proline with PYCR1 to diagnose asthma were 0.951 (95% CI 0.90–1, P < 0.05), 0.752 (95% CI 0.64–0.86, P < 0.05), and 0.964 (95% CI 0.93–1, P < 0.05), respectively, indicating a satisfying ability of proline and/or PYCR1 as biomarkers to distinguish patients with asthma from healthy controls (Figure 1, F–H).