Research on the role and mechanisms of Cystatin 6 in disease pathosis and development

The Cystatin 6 (CST6 [also known as Cystatin E/M]) is a cysteine protease inhibitor that exhibits a dual role in various types of tumors, acting as either a suppressor or promoter. In non-oncological contexts, CST6 maintains skin barrier homeostasis, mediates preeclampsia pathosis, and is associated with conditions such as pulmonary fibrosis. Diagnostic approaches involving CST6 include liquid biopsy and tissue analysis, while therapeutic strategies involve epigenetic activation and recombinant protein administration, among others. Overall, as a key variable driving multisystem pathologies through protease-substrate imbalance, CST6 represents a molecular target for precision diagnostics and therapeutics across diseases, necessitating in-depth investigation into its functions. Based on the existing research, this review summarizes the fundamental theory of CST6 in disease, considers its roles in both oncological and non-oncological conditions, and proposes future research directions.