ZFAS1 and digestive system cancer: The results of subgroup analysis demonstrated that the HRs of the high ZFAS1 expression group versus the low ZFAS1 expression group in digestive system cancers, nervous system cancers, respiratory system cancers and reproductive system cancers were 1.88 (95% CI = 1.30–2.73, P < 0.001), 2.21 (95% CI = 1.43–3.42, P < 0.001), 2.76 (95% CI = 1.85–4.12, P < 0.001) and 1.40 (95% CI = 0.71–2.76, P = 0.33), respectively (Table 2 and Figure 3).