Figure 4: Recurrence-free survival and overall survival stratified by STEAP4 methylation status. (a) Methylation of STEAP4 in tumor samples was significantly correlated with poor recurrence-free survival compared with unmethylated cases (p=0.0462). (b) Methylation of STEAP4 in tumor tissues was significantly correlated with poorer prognosis compared with unmethylated cases (p=0.0411).