KLC3 (kinesin light chain 3) is a microtubule-associated motor protein with diverse physiological and pathological roles. Originally characterized for spermiogenesis, where it participates in sperm midpiece development through interaction with mitochondria and outer dense fibers 1, recent evidence reveals broader oncogenic functions. In ovarian cancer, KLC3 is significantly upregulated and promotes cell proliferation, migration, and epithelial-mesenchymal transition (EMT) via the PI3K/AKT signaling pathway through COL3A1 interaction 2. Similarly, in gastric cancer, KLC3 stabilizes the fructose transporter SLC2A5, activating MAPK signaling and EMT 3. Beyond cancer, KLC3 regulates axonemal glutamylation through RAB11FIP5 interaction at basal bodies, contributing to cyst progression in polycystic kidney disease 4. Additionally, obesity-associated alterations in KLC3 expression link to Alzheimer's disease-related pathways 5. KLC3 also appears relevant in colorectal cancer drug resistance and may intersect with hemophagocytic lymphohistiocytosis genetics 67. However, targeted mouse models revealed that KLC3 inactivation surprisingly has no impact on fertility 1, questioning its necessity in reproduction. These findings establish KLC3 as a pleiotropic oncogenic driver in multiple cancer types while regulating ciliary function and metabolic processes.