Prospects of molecular hydrogen in cancer prevention and treatment

Gas signaling molecules, including carbon monoxide (CO), nitric oxide (NO), and hydrogen sulfide (H₂S), have been shown to have cancer therapeutic potential, pointing to a new direction for cancer treatment. In recent years, a series of studies have confirmed that hydrogen (H₂), a weakly reductive gas, also has therapeutic effects on various cancers and can mitigate oxidative stress caused by radiation and chemotherapy, reducing tissue damage and immunosuppression to improve prognosis. Meanwhile, H₂ also has immunomodulatory effects, inhibiting T cell exhaustion and enhancing T cell anti-tumor function. It is worth noting that human intestinal flora can produce large amounts of H₂ daily, which becomes a natural barrier to maintaining the body's resistance to diseases such as tumors. Although the potential anti-tumor mechanisms of H₂ are still to be investigated, previous studies have shown that H₂ can selectively scavenge highly toxic reactive oxygen species (ROS) and inhibit various ROS-dependent signaling pathways in cancer cells, thus inhibiting cancer cell proliferation and metastasis. The ROS scavenging ability of H₂ may also be the underlying mechanism of its immunomodulatory function. In this paper, we review the significance of H₂ produced by intestinal flora on the immune homeostasis of the body, the role of H₂ in cancer therapy and the underlying mechanisms, and the specific application of H₂ to provide new ideas for the comprehensive treatment of cancer patients.