RGX-104, also known as SB 742881, is a liver X receptor beta agonist with potential immunomodulating and antineoplastic activities. Upon oral administration, RGX-104 selectively targets and binds to LXRbeta, thereby activating LXRbeta-mediated signaling, leading to the transcription of certain tumor suppressor genes and the downregulation of certain tumor promoter genes. This particularly activates the expression of apolipoprotein E (ApoE), a tumor suppressor protein, in tumor cells and certain immune cells. This activates the innate immune system, resulting in depletion of immunosuppressive myeloid-derived suppressor cells (MDSCs), tumor cells and endothelial cells in the tumor microenvironment. This reverses immune evasion, enhances anti-tumor immune responses and inhibits proliferation of tumor cells.