MTHFR and cervical cancer: For example, in the meta-analysis investigating the association between MTHFR 677C>T polymorphism and cervical cancer under the allele contrast model (T versus C), the funnel plot’s shape was symmetrical, suggesting no presence of publication bias (Figure4); in addition, the P value of the Egger’s test for the allele contrast model was 0.744, providing statistical evidence for funnel plot symmetry.