In publicly accessible data from TCGA breast cancer cohort, the methylation levels of cg00452016 in NNT (rho = -0.16, p value = 2.6e−5) and cg01667837 in GPR37 (rho = -0.19, p value = 6.3e−7) were inversely correlated with their corresponding gene expression (Additional file 2: Fig. S2). Here, GPR37 is linked to breast cancer.