siRNA-mediated knockdown of GILZ in melanoma cells induced cellular dormancy by driving cells into G0-phase arrest. This was accompanied by decreased sphere and colony formation, delayed tumor initiation in mice, and activation of the FOXO3A/p21CIP1 signaling axis, confirmed through qRT-PCR, western blotting, flow cytometry, and immunofluorescence. The gene discussed is CDKN1A; the disease is neoplasm.