SPINT2 (Serine Peptidase Inhibitor, Kunitz Type 2) is a gene that encodes a serine protease inhibitor involved in regulating key cellular processes such as growth, migration, and invasion. Also known as HAI-2, SPINT2 helps control proteolytic activity—particularly by inhibiting matriptase, a protease important for epithelial integrity and signaling. Disruption of SPINT2 function has been linked to tumor development and progression, underscoring its role in maintaining tissue homeostasis and cancer suppression.