Our results demonstrated that miR-3922-5p was a direct target of HOXC-AS3, and PPP1R1A was a target of miR-3922-5p in breast cancer.<b>Conclusions:</b> The novel lncRNA HOXC-AS3 acts as a miR-3922-5p sponge to upregulate PPP1R1A protein expression, and thus results in promoting breast cancer metastasis.