Analysis of tumor and blood samples of patients with retinoblastoma (ORPHA:790) uncovered hypermethylation of cathepsin Z (CTSZ), metallothionein 1 H (MT1H) and homeobox C4 (HOXC4) genes as well as hypomethylation of the miR-17-92 (oncomir-1, a potent oncogenic miRNA) cluster, setting a specific methylation signature than can be used for diagnosis and therapeutic avenues (Berdasco et al., 2017). The gene discussed is MT1H; the disease is retinoblastoma.