HOTAIR and digestive system carcinoma: Subgroup analysis showed that the relationship between HOTAIR expression and differentiation was significant in estrogen-dependent carcinomas (OR = 2.12, 95% CI = 1.01–4.46, P = .04) with a moderate heterogeneity (I2 = 64.0%, P = .01) and OSCCs (OR = 2.73, 95% CI = 1.27–5.87, P = .010; I2 = 0.0%, P = .38) without any heterogeneity, but not in digestive system carcinomas (OR = 1.35, 95% CI = 0.76–2.41, P = .31) or other carcinomas (OR = 0.21, 95% CI = 0.05–0.97, P = .04).