RB1 and retinoblastoma: This gene, in fact, is poorly characterized; however, it is established to be involved in hydrogen sulfide metabolism by the means of S-sulfanylglutathione production.35, 36, 37 Hence, the very distinct and specifically lowered expression level of this gene potentially hints at the existence of differential metabolic dynamics within MYCN-amplified RB1-proficient retinoblastomas.