TPX2 (TPX2 microtubule nucleation factor) is a spindle assembly factor essential for normal mitotic spindle formation and microtubule nucleation during cell division 1. The protein mediates Aurora A kinase (AURKA) localization to spindle microtubules and activates AURKA through promoting autophosphorylation at Thr-288 while protecting against dephosphorylation 2. TPX2 function is regulated by importin-alpha binding, which inactivates the protein; liberation from importin-alpha at mitosis onset allows TPX2 to activate AURKA and stimulate microtubule nucleation 3. Beyond mitotic functions, TPX2 plays dual roles in DNA damage response by controlling double-strand break repair pathway choice through ATM-mediated S634 phosphorylation, which promotes BRCA1 recruitment for homologous recombination, while non-phosphorylated TPX2 facilitates 53BP1-mediated non-homologous end joining 4. TPX2 is frequently overexpressed in multiple cancer types including breast cancer, renal cell carcinoma, and multiple myeloma, correlating with increased proliferation, invasion, and poor prognosis 567. The AurkA/TPX2 complex represents a potential oncogenic unit that promotes chr20 instability and tumor progression 2, making it an attractive therapeutic target for cancer treatment.