DEFB128 (defensin beta 128) is an antimicrobial peptide with primary antibacterial activity against both Gram-negative and Gram-positive bacteria. As a member of the beta-defensin family, it functions as part of the innate immune response at mucosal surfaces, contributing to the epithelial barrier's protective mechanisms 1. In healthy gingival tissues, DEFB128 is expressed at intermediate to low levels and exhibits dynamic regulation during periodontal disease progression, with expression generally decreased in response to infection and inflammation 1. The gene is located within a frequently amplified region (20p13) in tongue cancer tissues, where it co-amplifies with adjacent defensin genes (DEFB125, DEFB126, DEFB127, DEFB129, DEFB132) and other genes in primary tumors and recurrent lesions 2. Beyond its antimicrobial function, DEFB128 has emerging clinical significance as a danger-recognizing peptide. Elevated serum levels of β-defensin-128 are independently associated with recurrent coronary events in subjects with coronary artery disease, with an odds ratio of 7.49, and combining β-defensin-128 with histatin-3 improved risk prediction for recurrent events (C-statistics: 0.800 versus 0.677 for conventional factors alone) 3. This suggests DEFB128 may serve as a biomarker for cardiovascular risk stratification.