Twenty-four studies reported the association of B7x with tumor differentiation (well and moderate vs poorly), significant heterogeneity was proved by testing (I2 = 33.5%, P = .06), and using a random-effect model, the results showed that B7x was associated with tumor differentiation (OR = 2.95, 95% CI = 1.91–4.57, P < .001) (Fig. 4). This evidence concerns the gene VTCN1 and neoplasm.