The c-Myc oncogene encodes a transcription factor, c-Myc, which is involved in the regulation of the cell cycle. C-Myc belongs to the Myc family of proteins including B-Myc, L-Myc, N-Myc, and s-Myc. c-Myc is a b-HLH-LZ (basic helix-loop-helix-leucine zipper) protein that must form a heterodimer with another b-HLH-LZ protein, Max, in order to bind DNA and activate transcription.
Mutations in myc proteins or overexpression of their encoding genes have been linked to several forms of cancer, among these are lymphoma, myeloma, liver, lung, and breast cancer.