MT1G (metallothionein 1G) is a cysteine-rich protein encoded on chromosome 16 that primarily functions in metal homeostasis and cellular protection. 1 MT1G binds heavy metals including cadmium, copper, and zinc, providing detoxification and maintaining intracellular metal ion balance. 2 Beyond metal binding, MT1G regulates oxidative stress responses and ferroptosis pathways, with emerging roles in cancer biology. In osteosarcoma, MT1G expression is elevated and correlates with metastatic potential and poor survival, suggesting involvement in tumor progression. 3 Conversely, in prostate cancer, MT1G is downregulated, and its overexpression inhibits cancer cell growth while modulating the tumor microenvironment to enhance immunotherapy sensitivity. 4 In gastric cancer, MT1G overexpression promotes ferroptosis and iron autophagy through GPX4/SQSTM1 axis modulation, suppressing cancer cell proliferation and invasion. 5 Recent evidence indicates MT1G serves as a biomarker for cancer prognosis and therapeutic response across multiple malignancies. 6 Additionally, MT1G responds to cellular stress signals; sucralose-6-acetate exposure significantly upregulated MT1G expression in intestinal epithelium, suggesting its role in response to chemical toxins. 7 MT1G is also regulated by tumor-derived extracellular vesicles carrying miR-1290, linking its function to cancer cell-fibroblast interactions in the tumor microenvironment.