S100A10, also known as p11 or annexin 2 light chain, is a member of the S100 family of calcium - binding proteins. Uniquely, it does not bind to Ca2+ despite sequence and structural similarities to other family members. It mainly binds to annexin A2 to form a heterotetrameric complex (AIIt), which is crucial for the conversion of plasminogen to plasmin, a process involved in multiple physiological processes such as fibrinolysis, angiogenesis, and wound healing [2,3,4,5,7].

In cancer research, S100A10 - deficient mice have shown reduced cancer metastasis in the lung [6]. Tumor - derived exosomes can activate S100A10 in lung fibroblasts, increasing the expression of CXCL1 and CXCL8 chemokines and recruiting myeloid - derived suppressor cells (MDSCs), thus promoting cancer metastasis. In hepatocellular carcinoma (HCC), S100A10 promotes HCC initiation, self - renewal, chemoresistance, and metastasis both in vitro and in vivo. S100A10 is secreted by HCC cells into extracellular vesicles (EVs), and EV - S100A10 enhances the stemness and metastatic ability of HCC cells, upregulates epidermal growth factor receptor (EGFR), AKT, and ERK signalling, and promotes epithelial - mesenchymal transition [1].

In conclusion, S100A10 plays a significant role in physiological processes related to plasmin generation. In disease, especially cancer, S100A10 - related KO mouse models have revealed its promoting effect on cancer metastasis, highlighting its potential as a therapeutic target and biomarker, especially in lung cancer and HCC [1,6].