MALAT1 and digestive system cancer: A significant relationship was observed between MALAT1 overexpression and poor OS in the studies for digestive system cancers (pooled HR = 1.77, 95 % CI 1.18–2.35), urinary system cancers (pooled HR = 2.95, 95 % CI 1.43–4.46), and respiratory system cancers (pooled HR = 1.72, 95 % CI 0.86–2.57) (Fig. 2b).