MT1H (metallothionein 1H) is a cysteine-rich metal-binding protein encoded on chromosome 16 as one of eight functional MT1 isoforms 1. As a member of the metallothionein family, MT1H participates in metal homeostasis and cellular defense against heavy metals, oxidative stress, and DNA damage 1. MT1H expression is transcriptionally regulated by metal ions (particularly zinc) and glucocorticoids (dexamethasone) 2. Mechanistically, MT1H functions as a tumor suppressor across multiple cancer types. In gastric cancer, nuclear-localized MT1H regulates nutrient transporter genes (SLC6A19, TTC39B, ADM2) and activates p53-dependent autophagy 2. In hepatocellular carcinoma, MT1H inhibits Wnt/β-catenin signaling through the Akt/GSK-3β axis 3. In colon cancer, MT1H interacts with DUSP1 to suppress MAPK signaling (ERK, JNK, p38) 4. In prostate cancer, MT1H's tumor suppressor activity depends on interaction with euchromatin histone methyltransferase 1 (EHMT1) 5. Clinically, MT1H downregulation correlates with poor prognosis in multiple malignancies 35, while high expression predicts improved survival in gastric cancer 2. MT1H also associates with therapy resistance in HER2-positive esophagogastric cancer 6. These findings position MT1H as a potential biomarker and therapeutic target in cancer.