HSF2BP is a meiotic recombination factor essential for double-strand break (DSB) repair and fertility. Primary function: HSF2BP modulates localization of recombinases DMC1 and RAD51 to meiotic DSB sites through interaction with BRCA2 and its binding partner BRME1 123. Mechanism: HSF2BP forms oligomeric complexes with BRCA2 that are regulated by BRME1, controlling recombinase recruitment and BRCA2 turnover during homologous recombination 3. The protein's armadillo repeat domain interacts with a conserved region of BRCA2 between the BRC repeats and DNA-binding domain 14. Disease relevance: HSF2BP mutations cause primary ovarian insufficiency (POI), a major cause of infertility 52. A missense variant (S167L) in HSF2BP reduces fertility through impaired meiotic recombination and decreased RAD51/DMC1 foci formation 2. Clinical significance: HSF2BP is indispensable for male spermatogenesis and female meiosis I progression 1. Beyond reproduction, HSF2BP is implicated in lung adenocarcinoma progression through BNC1/TGF-β/SMAD3 signaling, affecting tumor proliferation and immune evasion 6. Genetic screening for HSF2BP mutations is warranted in POI patients for improved genetic counseling 5.