Cysteine-rich secretory proteins (CRISPs) represent a family of evolutionarily conserved proteins which play a role in the innate immune system and are transcriptionally regulated by androgens in several tissues. CRISP-8 (Cysteine-rich secretory protein 8), also known as PI15 (Peptidase inhibitor 15), P25TI or SugarCrisp, is a 258 amino acid secreted protein that belongs to the CRISP family. Expressed at low levels in thyroid, prostate, salivary and mammary tissue, CRISP-8 functions as a serine protease inhibitor that exhibits weak inhibitory action against Trypsin, a serine protease found in the digestive system. In addition to its role as a protease inhibitor, CRISP-8 is secreted in neuroblastoma and glioblastoma cell lines, suggesting a role for CRISP-8 in tumor formation and metastasis within the central nervous system.