AFP and hepatocellular carcinoma: In the current meta-analysis, the Spearman correlation coefficients of DKK-1 alone, AFP alone, and DKK-1 + AFP in diagnosing HCC were 0.378 (P = .226), −0.050 (P = .898), and 0.119 (P = .779), which indicated that threshold effect did not exist as all P-values were >.05.