Mgp, also known as Matrix Gla protein, is a vitamin K-dependent post-translationally modified protein. It is a potent inhibitor of extracellular matrix mineralization, playing a key role in preventing ectopic calcification in tissues like cartilage and the vascular system. Mutations in the Mgp gene cause Keutel syndrome, characterized by abnormal cartilaginous and vascular calcification [2,5].

In cancer research, Mgp has been found to be involved in multiple processes. In colorectal cancer, Mgp promotes CD8+ T cell exhaustion by activating the NF-κB pathway, leading to liver metastasis. Inhibition of Mgp significantly decreased the rate of liver metastasis, and combined with αPD1, it synergistically resisted metastasis [1]. In colon cancer, Mgp promotes cell growth and proliferation by enriching intracellular calcium concentration and activating the NF-κB pathway, being associated with a worse prognosis [6]. In breast cancer, Mgp+ tumor-associated macrophages influence the efficacy of immunotherapy, with increased numbers of these macrophages upregulating pro-tumorigenic factors after anti-PD-1 treatment [3]. Also, Mgp is overexpressed in CRC and may confer resistance to oxaliplatin, and its knockdown can reverse this resistance [4]. In a study on specific heterozygous variants in Mgp in humans, heterozygous 'knock-in' mice expressing one of the variants (C19F) recapitulated most of the skeletal anomalies observed in affected individuals, suggesting endoplasmic reticulum stress-induced apoptosis of growth plate chondrocytes as the main mechanism for the observed spondyloepiphyseal skeletal dysplasia [2].

In conclusion, Mgp has essential functions in preventing ectopic calcification. In disease models, especially in cancer and certain skeletal dysplasia, Mgp plays significant roles. Gene-based models such as the 'knock-in' mouse model for Mgp have been crucial in revealing its role in biological processes and disease conditions, providing insights into potential therapeutic targets for related diseases.