GCG and prediabetes syndrome: The increase in SFRP4 blood levels in people with prediabetes indicates that this protein has potential as an early biomarker of T2D and as a therapeutic target in pancreatic islet dysfunction, as suggested by Wilson et al. [35] However, further studies that consider the follow-up of prediabetes patients are required, and it would be interesting to include patients with complications, as well as studies that include insulin and glucagon measures, to understand the role of SFRP4 in T2D development.