# Prospects of molecular hydrogen in cancer prevention and treatment.
> 分子状水素によるがん予防・抑制の可能性：腸内フローラ産生H₂と免疫調節を中心としたレビュー


## Abstract

Gaseous signaling molecules such as carbon monoxide, nitric oxide, and hydrogen sulfide have established precedents for gas-based oncological applications. Hydrogen gas (H₂), a mildly reductive molecule, has emerged as a candidate in this field. Evidence indicates that H₂ selectively neutralizes highly reactive oxygen species (ROS) and suppresses ROS-dependent intracellular signaling, thereby reducing cancer cell proliferation and metastatic potential. In the context of radiation and chemotherapy, H₂ appears to attenuate oxidative tissue damage and immunosuppression, with potential implications for prognosis. Immunologically, H₂ has been associated with inhibition of T cell exhaustion and enhancement of anti-tumor T cell activity. Notably, the human gut microbiota constitutes a continuous endogenous source of H₂, which may contribute to systemic tumor resistance. This review consolidates current understanding of gut-flora-derived H₂ and immune homeostasis, the mechanistic basis of H₂'s anti-tumor activity, and practical delivery considerations, aiming to inform future research directions in comprehensive cancer care.

### Mechanism

H₂ selectively scavenges highly cytotoxic ROS such as hydroxyl radicals and peroxynitrite, suppressing ROS-dependent signaling pathways that drive cancer cell proliferation and metastasis; this ROS-neutralizing capacity is also proposed to underlie H₂'s immunomodulatory effects, including inhibition of T cell exhaustion and enhancement of anti-tumor immune responses.

## Bibliographic

- **Authors**: Zhou W, Zhang JH, Chen W, Miao C
- **Journal**: J Cancer Res Clin Oncol
- **Year**: 2024 (2024-03-31)
- **PMID**: [38555538](https://pubmed.ncbi.nlm.nih.gov/38555538/)
- **DOI**: [10.1007/s00432-024-05685-7](https://doi.org/10.1007/s00432-024-05685-7)
- **PMC**: [PMC10982102](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10982102/)
- **Study type**: review
- **Delivery route**: mixed routes
- **Effect reported**: not assessed

## Delivery context

This study combines multiple delivery routes. As a general principle, the most efficient route for routine hydrogen intake is inhalation. Inhalation carries explosion risk (empirical LFL of 10%; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

## Safety notes

This study combines multiple delivery routes. As a general principle, the most efficient route for routine hydrogen intake is inhalation. Inhalation carries explosion risk (empirical LFL of 10%; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 38555538. https://h2-papers.org/en/papers/38555538
> **Source**: PubMed PMID [38555538](https://pubmed.ncbi.nlm.nih.gov/38555538/)