The Effectiveness of Traditional Chinese Medicine in Treating Malignancies via Regulatory Cell Death Pathways and the Tumor Immune Microenvironment: A Review of Recent Advances

Traditional Chinese Medicine (TCM) has achieved high clinical efficacy in treating malignancies in recent years and is thus gradually becoming an important therapy for patients with advanced tumor for its benefits in reducing side effects and improving patients' immune status. However, it has not been internationally recognized for cancer treatment because TCM's anti-tumor mechanism is not fully elucidated, limiting its clinical application and international promotion. This review traced the mechanism of the TCM-mediated tumor cell death pathway and its effect on remodeling the tumor immune microenvironment, its direct impact on the microenvironment, its anti-tumor effect in combination with immunotherapy, and the current status of clinical application of TCM on tumor treatment. TCM can induce tumor cell death in many regulatory cell death (RCD) pathways, including apoptosis, autophagy, pyroptosis, necroptosis, and ferroptosis. In addition, TCM-induced cell death could increase the immune cells' infiltration with an anti-tumor effect in the tumor tissue and elevate the proportion of these cells in the spleen or peripheral blood, enhancing the anti-tumor capacity of the tumor-bearing host. Moreover, TCM can directly affect immune function by increasing the population or activating the sub-type immune cells with an anti-tumor role. It was concluded that TCM could induce a pan-tumor death modality, remodeling the local TIME differently. It can also improve the systemic immune status of tumor-bearing hosts. This review aims to establish a theoretical basis for the clinical application of TCM in tumor treatment and to provide a reference for TCM's potential in combination with immunotherapy in cancer treatment.