PROCA1 (protein interacting with cyclin A1) is a cyclin-binding protein located on chromosome 17 with emerging roles in reproductive and cancer biology. PROCA1 functions as an interaction partner of the cyclin A1-CDK2 complex, linking it to DNA repair, cell signaling, and splicing pathways 1. The protein is predominantly expressed in testis, where it localizes to the acrosome of sperm 2. In reproductive biology, PROCA1 mutations have been identified in patients with acrosome-deficient teratozoospermia 2, though knockout mouse models showed normal fertility and acrosome development, suggesting species-specific functional requirements 2. In cancer biology, PROCA1 plays a tumor-suppressive role in lung adenocarcinoma by recruiting ZFP36L2 to destabilize BCL2 mRNA, thereby promoting apoptosis and cisplatin chemosensitivity 3. Additionally, PROCA1 functions as a hub fatty acid metabolism-related gene affecting PD-1 expression and T cell infiltration in head and neck squamous cell carcinoma, influencing anti-PD1 immunotherapy efficacy 4. PROCA1 also serves as a prognostic biomarker in colorectal cancer within lipid metabolism-related gene signatures 5. These findings establish PROCA1 as a multifunctional protein with potential clinical significance in cancer treatment response prediction.