Among those cancer-associated miRNAs, miR-126 was first identified as an miRNA regulating human megakaryocytopoiesis.[15] Further studies reported that miR-126 was involved in progression of angiogenesis, proliferation, migration, invasion, and cell survival by targeting several important genes such as CADM1, PAK4, and SOX2.[16–18] So far, circulating miR-126 has been reported that it could act as a significant biomarker in the prognosis of various cancers.[19] Additionally, plenty of studies have focused on the diagnosis use of circulating miR-126. This evidence concerns the gene SOX2 and cancer.