LDHC (lactate dehydrogenase C) is a testis-specific isozyme primarily localized to the sperm tail that plays critical roles in male fertility and metabolic regulation 1. In spermatozoa, LDHC catalyzes the interconversion of pyruvate and lactate as part of anaerobic glycolysis, providing energy for sperm motility and capacitation 2. Ldhc knockout mice exhibit impaired sperm motility and reduced fertilizing capacity, demonstrating its essential function in reproduction 3. Beyond reproduction, LDHC functions in lactate metabolism across tissues, oxidizing lactate to pyruvate to re-enter the TCA cycle 4. In cancer contexts, LDHC acts as a cancer-testis antigen with immunomodulatory properties. High LDHC expression in lung adenocarcinoma correlates with aggressive clinicopathological features and poor prognosis, operating through PI3K/Akt/GSK-3β pathway activation to promote proliferation and epithelial-mesenchymal transition 5. Conversely, LDHC knockdown in breast cancer enhances anti-tumor immunity by reducing T cell dysfunction and immune checkpoint expression 6. LDHC also suppresses B-cell mediated inflammation in osteoarthritis 7. These findings identify LDHC as a multifunctional target for contraceptive, immunotherapeutic, and metabolic interventions 8.