MYCN, also named as BHLHE37 and NMYC, is a transcription factor. It is primarily expressed in normal developing embryos and is thought to be critical in brain and other neural development. It is often amplified in human neuroblastomas. IR34A can suppress MYCN expression, it suggest MYCN has a role in cell growth. The expression of the MCYN is upregulated in a variety of human tumors, most frequently neuroblastoma, where the level of expression appears to increase as the tumor progresses. The calculated molecuar weight of MYCN is 50 kDa, but Phosphorylated MYCN is about 65-70 kDa. MYCN exsits two isoforms and MV of isoform is respectively 65 kDa and 45 kDa. (PMID: 19615087 )