Myc is a family of regulator genes and proto-oncogenes that code for transcription factors. The Myc family consists of three related human genes: c-myc (MYC), l-myc (MYCL), and n-myc (MYCN). c-myc (also sometimes referred to as MYC) was the first gene to be discovered in this family, due to homology with the viral gene v-myc.

In cancer, c-myc is often constitutively (persistently) expressed. This leads to the increased expression of many genes, some of which are involved in cell proliferation, contributing to the formation of cancer. A common human translocation involving c-myc is critical to the development of most cases of Burkitt lymphoma. Constitutive upregulation of Myc genes have also been observed in carcinoma of the cervix, colon, breast, lung and stomach.

Myc is thus viewed as a promising target for anti-cancer drugs. Unfortunately, Myc possesses several features that render it undruggable, such that any anti-cancer drugs for Myc dysregulation will require acting on the protein indirectly, such as by targeting the mRNA for the protein rather than a small molecule that targets the protein itself.

c-Myc also plays an important role in stem cell biology and was one of the original Yamanaka factors used to reprogram somatic cells into induced pluripotent stem cells.

In the human genome, C-myc is located on chromosome 8 and is believed to regulate expression of 15% of all genes through binding on enhancer box sequences (E-boxes).

In addition to its role as a classical transcription factor, N-myc may recruit histone acetyltransferases (HATs). This allows it to regulate global chromatin structure via histone acetylation.