VISTA immune regulatory effects in bypassing cancer immunotherapy: Updated

Resistance to immune checkpoint inhibitors (ICIs) is a common predicament in cancer immunotherapy, which requires urgent interventions. V-domain immunoglobulin suppressor of T cell activation (VISTA) or programmed death-1 homolog (PD-1H) is a molecule belong to the CD28/B7 family that acts as an immune checkpoint and a negative immune regulator. VISTA shows high expression within tumor microenvironment (TME) and shapes the immune landscape of this milieu into an immunosuppressive entity through blunting the activity of anti-tumor cells and strengthening the power of pro-tumor cells. The increased expression profile is occurring essentially after inhibition of other checkpoints, which indicates that VISTA can constitute a novel and complementary target in cancer immunotherapy. Combination of anti-VISTA with appropriate ICIs potentiates tumor immunogenicity through increasing the effector activity of T cells, and results in more pronounced responses. VISTA also serves as a prognostic biomarker in differentiating early- from late-stage cancer. In this review, we aimed to discuss about VISTA and its regulation within TME and focusing on its prognostic and therapeutic values in cancer immunotherapy.