High-mobility group AT-hook 2 (HMGA2) is a chromatin factor that regulates transcription and cellular differentiation during embryonic development. HMGA2 helps to regulate the cell cycle and plays an important role in chromosome condensation during the meiotic G2/M transition of spermatocytes. It also interacts with transcription factor E4F1, protein kinase NEK2, and the promoter of the nucleotide excision-repair gene ERCC1 to negatively modulate its activity.   HMGA2 expression in adult tissues is often associated with benign and malignant tumor formation. HMGA2 is expressed in most conventional and intramuscular lipomas, 84 and 100%, respectively and can aid in differentiating between lipomas from dedifferentiated liposarcomas and distinguishing areas of tumor from normal adipose tissue.  In mesenchymal tumors, HMGA2 is expressed in 88% of benign fibrous histiocytoma, 90% of nodular fasciitis, and 90% of vulvovaginal angiomyxoma.    Increased expression of HMGA2 occurs in other human malignancies, including pancreatic, gastric, oral squamous cell, ovarian, and a subset of breast cancers. In thyroid carcinomas, upregulation of HMGA2 can distinguish between benign and malignant follicular neoplasias. Further, HMGA2 overexpression is often found in non-small cell lung cancer and could be used as a marker for lung carcinomas. The presence of HMGA2 in cancer is correlative with metastasis and poor prognosis.