Implications of regulatory T cells in anti-cancer immunity: from pathogenesis to therapeutics

Regulatory T cells (Tregs) play an essential role in maintaining immune tolerance and suppressing inflammation. However, Tregs present major hurdle in eliciting potent anti-cancer immune responses. Therefore, curbing the activity of Tregs represents a novel and efficient way towards successful immunotherapy of cancer. Moreover, there is an emerging interest in harnessing Treg-based strategies for augmenting anti-cancer immunity in different types of the disease. This review summarises the crucial mechanisms of Tregs’ mediated suppression of anti-cancer immunity and strategies to suppress or to alter such Tregs to improve the immune response against tumors. Highlighting important clinical studies, the review also describes current Treg-based therapeutic interventions in cancer, and discusses Treg-suppression by molecular targeting, which may emerge as an effective cancer immunotherapy and as an alternative to detrimental chemotherapeutic agents. •Tregs are crucial in maintaining immune tolerance and suppressing inflammation.•Tregs present a major obstacle to eliciting potent anti-tumor immune responses.•The review summarizes current Treg-based therapeutic interventions in cancer.•Treg can be an effective cancer immunotherapy target. Anti-cancer immunity; Cancer, CD8+ T cells; CD4+ T cells; Regulatory T cells; Tumor-infiltrating lymphocytes.