SLC31A1 and cancer: High CTR1 expression was correlated with a favorable OS and PFS in cancers (for OS, HR = 0.64, 95% CI: 0.50-0.82, P = 0.000; for PFS, HR = 0.65, 95% CI: 0.57-0.75, P = 0.000) (Figure 3 and Figure 4).