Cancer is a group of malignant diseases and is one of the leading causes of death worldwide. Current treatments can be invasive and nonspecific, therefore killing healthy cells along with cancerous cells. In many types of cancers including lymphoma, signal transducer and activator of transcription 3 (STAT3) is upregulated and regarded as a risk factor for its enhancing tumorigenicity. Thus, STAT3 is a target for cancer therapy. In this project, we explored a viral protein called nsp5 that induces the degradation of STAT3 to develop cancer therapeutics against lymphoma. We cloned the nsp5 gene into a retroviral expression system and determined its expression. Replication-defective retrovirus particles were packaged and used to deliver nsp5 gene into the lymphoma-derived cells. The nsp5 effect on downregulation of STAT3 and tumor cell growth were determined. These results demonstrate that the viral protein can be explored for further preclinical development for potential tumor therapeutics.