PMCH and neoplasm: Although the trend of MCH level was different in tumor mice and healthy mice, the final aggregate effect showed no difference with the control group [n=34, MD=-0.21, 95%CI (-0.57, 0.14), P=0.24; Heterogeneity: Chi2 = 9.71, df=3 (P=0.02), I2 = 69%] (Figure 4D).