SIRT6 and digestive system neoplasm: Low SIRT6 expression was associated with a better OS in breast cancer (HR = 0.49, 95% CI = 0.27–0.89, P = 0.179), but was associated with a worse OS in gastrointestinal tumours (HR = 0.30, 95% CI = 0.10–0.91, P = 0.069).