Oncogenes: Myc

The myc protein acts as a transcription factor and it controls the expression of several genes. Mutations in the myc gene have been found in many different cancers, including Burkitt's lymphoma, B-cell leukemia, and lung cancer. The myc family of oncogenes may become activated by gene rearrangement or amplification. Gene rearrangements involve the breakage and reunion of chromosomes. This process can involve large amounts of DNA and can affect many genes. The movement of a gene or group of genes to a different location within the same chromosome or to a different chromosome often leads to altered gene expression and cell function.

Translocation is one type of gene rearrangement, and a translocation between chromosomes 8 and 14 has been shown to result in overexpression of myc and ultimately B-cell lymphoma. The animation below shows what a translocation between two different chromosomes looks like.

The amount of myc protein present in the cell is important because the activity of myc is balanced by another protein that opposes myc activity. Therefore, an increase in either protein will offset the balance and affect cell division.⁽¹⁾>

In the video above, Dr. Gerard Evan discusses the role myc protein in cancer.  Watch the full interview with Dr. Evan.

An increase in myc activity is sometimes associated with programmed cell death, but this safeguard seems to be overridden in the presence of another oncogene, bcl-2, which prevents myc induced apoptosis.⁽¹⁾

1. Cooper G. Oncogenes. Jones and Bartlett Publishers, 1995. 151-152, 175-176.