DNMT1 and retinoblastoma: Accordingly, a recent study from Jin et al. (2021) has not only shown that PAX5 is hypermethylated in retinoblastoma tumors but also, the treatment of patients with cyclophosphamide (a common antineoplastic agent to treat retinoblastoma) increases PAX5 expression via gene demethylation and concomitant DNMT inhibition, which result in tumor regression [104,157].