Myotrophin (MTPN) is a multifunctional protein that plays critical roles in insulin secretion regulation and chemotherapy resistance. In pancreatic β-cells, MTPN is a direct target of microRNA-375 (miR-375), where miR-375 down-regulates MTPN expression to reduce glucose-induced insulin secretion 1. This regulatory axis is essential for pancreatic development and function, with miR-375 controlling MTPN to influence insulin secretion pathways 2. In cancer contexts, MTPN promotes chemotherapy resistance through multiple mechanisms. In pancreatic cancer with wild-type BRCA1/2, MTPN induces cisplatin resistance by activating NF-κB signaling and upregulating BRCA1/2 expression to enhance DNA repair 3. Similarly, in cholangiocarcinoma, MTPN contributes to drug resistance, but this can be reversed through the arsenic trioxide/miR-885-5p/MTPN axis, where miR-885-5p targets MTPN to restore chemotherapy sensitivity 4. Additionally, MTPN has emerged as a potential biomarker in post-COVID-19 conditions, being identified among proteins with altered abundance in post-COVID-19 postural orthostatic tachycardia syndrome patients, suggesting involvement in immune and neuronal cell functions 5. These findings establish MTPN as a key regulatory protein in metabolic and oncological contexts.