High FoxP3+ Tregs densities were associated with significantly shorter OS in cervical (OR 5.11, 95% CI 2.87 to 9.11, P < 0.001), renal (OR 4.26, 95% CI 2.18 to 8.34, P < 0.001), melanomas (OR 2.15, 95% CI 1.34 to 3.44, P = 0.002), hepatocellular (OR 1.82, 95% CI 1.16 to 2.86, P = 0.009), gastric (OR 1.65, 95% CI 1.08 to 2.52, P = 0.02), and breast cancers (OR 1.65, 95% CI 1.13 to 2.41, P = 0.13). Here, FOXP3 is linked to breast cancer.