Stromal antigen 2 (STAG2) is a subunit of the cohesion complex that plays an important role in the normal segregation of sister chromatids during mitosis or meiosis, DNA repair, gene expression regulation, genomic imprinting, and the epithelial-to-mesenchymal transition (EMT). Because EMT is a key step in cancer cell metastasis, functional defects in cohesin may be related to both the occurrence and metastasis of cancer.