The present disclosure provides meroduplex ribonucleic acid molecules (mdRNA) capable of decreasing or silencing MYC gene expression. An mdRNA of this disclosure comprises at least three strands that combine to form at least two non-over-lapping double-stranded regions separated by a nick or gap wherein one strand is complementary to a MYC mRNA. In addition, the meroduplex may have at least one uridine substituted with a 5-methyluridine, a nucleoside replaced with a locked nucleic acid, or optionally other modifications, and any combination thereof. Also provided are methods of decreasing expression of a MYC gene in a cell or in a subject to treat a MYC-related disease.