Human neoplasias, including thyroid, prostatic, cervical, colorectal, pancreatic and ovarian carcinoma, show a strong increase of HMGA1a and HMGA1b proteins.[50] Transgenic mice with HMGA1 targeted to lymphoid cells develop aggressive lymphoma, showing that high HMGA1 expression is not only associated with cancers, but that the HMGA1 gene can act as an oncogene to cause cancer.[51] Baldassarre et al.,[52] showed that HMGA1 protein binds to the promoter region of DNA repair gene BRCA1 and inhibits BRCA1 promoter activity. They also showed that while only 11% of breast tumors had hypermethylation of the BRCA1 gene, 82% of aggressive breast cancers have low BRCA1 protein expression, and most of these reductions were due to chromatin remodeling by high levels of HMGA1 protein.