GATA2 or GATA-binding factor 2 is a transcription factor, i.e. a nuclear protein which regulates the expression of genes. It regulates many genes that are critical for the embryonic development, self-renewal, maintenance, and functionality of blood-forming, lympathic system-forming, and other tissue-forming stem cells. GATA2 is encoded by the GATA2 gene, a gene which often suffers germline and somatic mutations which lead to a wide range of familial and sporadic diseases, respectively. The gene and its product are targets for the treatment of these diseases. Inactivating mutations of the GATA2 gene cause a reduction in the cellular levels of GATA2 and the development of a wide range of familial hematological, immunological, lymphatic, and/or other disorders that are grouped together into a common disease termed GATA2 deficiency. Less commonly, these disorders are associated with non-familial (i.e. sporadic or acquired) GATA inactivating mutations. GATA2 deficiency often begins with seemingly benign abnormalities but if untreated progresses to life-threatening opportunistic infections, virus-induced cancers, lung failure, the myelodysplastic syndrome (i.e. MDS), and/or acute myeloid leukemia, principally acute myeloid leukemia (AML), less commonly chronic myelomonocytic leukemia (CMML), and rarely a lymphoid leukemia. Overexpression of the GATA2 transcription factor that is not due to mutations in the GATA2 gene appears to be a secondary factor that promotes the aggressiveness of non-familial EVI1 positive AML as well as the progression of prostate cancer. GATA2 gene The GATA2 gene is a member of the evolutionarily conserved GATA transcription factor gene family. All vertebrate species tested so far, including humans and mice, express 6 GATA genes, GATA1 through GATA6. The human GATA2 gene is located on the long (or "q") arm of chromosome 3 at position 21.3 (i.e. the 3q21.3 locus) and consists of 8 exons. Two sites, termed C-ZnF and N-ZnF, of the gene code for two Zinc finger structural motifs of the GATA2 transcription factor. These sites are critical for regulating the ability of the transcription factor to stimulate its target genes. The GATA2 gene has at least five separate sites which bind nuclear factors that regulate its expression. One particularly important such site is located in intron 4. This site, termed the 9.5 kb enhancer, is located 9.5 kilobases (i.e. kb) down-stream from the gene's transcript initiation site and is a critically important enhancer of the gene's expression. Regulation of GATA2 expression is highly complex. For example, in hematological stem cells, GATA2 transcription factor itself binds to one