RASSF1 and cancer: Figure 2 shows the forest plot of the associations between RASSF1A methylation and OS for all the cancer patients, where it can be seen that there was significant statistical heterogeneity among the included studies. The combined results of the random effect models suggested a significant relationship between RASSF1A methylation and OS (P < 0.001). Therefore, cancer patients with RASSF1A methylated may have a significantly increased risk of a poor survival prognosis.