MT1X (metallothionein 1X) is a member of the metallothionein family that primarily functions in cellular metal homeostasis and protection against oxidative stress 1. As a cysteine-rich protein, MT1X binds various heavy metals including zinc, copper, and cadmium, playing crucial roles in intracellular zinc ion homeostasis and detoxification processes 2. The protein is subject to autophagic degradation through E2F4-mediated autophagy pathways, which regulates zinc distribution within cells and affects cancer cell growth and metastasis 2. In cancer contexts, MT1X exhibits complex roles: it acts as a tumor suppressor in breast cancer where overexpression inhibits cell viability, migration, and invasion 3, while serving as an oncogene in clear cell renal cell carcinoma (ccRCC) where it correlates with poor prognosis and promotes cell growth 4. MT1X expression is regulated by miR-376a-3p in acute myeloid leukemia, where its downregulation increases apoptosis and sensitizes cells to chemotherapy 5. The protein interacts with TCRP1 and activates PI3K/Akt/NF-κB signaling pathways, contributing to cisplatin resistance in oral squamous cell carcinoma 6. Additionally, MT1X contains a T20 mononucleotide repeat in its 3'-UTR that serves as a highly sensitive and specific marker for microsatellite instability in colorectal cancer 7.