KIF4A is a multifunctional motor protein essential for proper chromosome X and cell division. As a chrX, KIF4A plays dual roles in mitosis: it directly binds the condensin I complex via a conserved motif in its C-terminal tail to activate chromosome X 1, and it translocates PRC1 to interdigitating spindle microtubules during anaphase to assemble the central spindle midzone required for cytokinesis 2. During spindle elongation, KIF4A functions as a crosslinker-assisted motor alongside EG5/kinesin-5 to drive microtubule sliding and chromosome X 3. Beyond canonical mitotic functions, KIF4A is aberrantly expressed across diverse cancers where it typically promotes tumorigenesis, therapy resistance, and metabolic reprogramming through enhanced glycolysis and cancer stemness 456. KIF4A overexpression correlates with poor prognosis in hepatocellular carcinoma and osteosarcoma 57, though paradoxically shows tumor-suppressive effects in cervical cancer 4. Germ-line KIF4A mutations cause X-linked intellectual disability type 100 (XLID100), characterized by intellectual impairment, language delay, and autism 8. The essential nature of KIF4A in mitosis and neuronal function complicates therapeutic targeting, necessitating tumor-selective delivery strategies 4.