The study by Zhao et al. reported that circ_0075804 was upregulated in retinoblastoma (RB), which improved the stability of its host gene E2F3 mRNA and promoted the proliferation of RB by binding to the nucleic acid binding protein heterogeneous nuclear ribonucleoprotein K (HNRNPK) [40]. The gene discussed is HNRNPK; the disease is retinoblastoma.