Fusion gene

A fusion gene is a hybrid gene formed from two previously separate genes. It can occur as a result of: translocation, interstitial deletion, or chromosomal inversion.

History

The first fusion gene was described in cancer cells in the early 1980s. The finding was based on the discovery in 1960 by Peter Nowell and David Hungerford in Philadelphia of a small abnormal marker chromosome in patients with chronic myeloid leukemia - the first consistent chromosome abnormality detected in a human malignancy, later designated the Philadelphia chromosome. In 1973, Janet Rowley in Chicago showed that the Philadelphia chromosome had originated through a translocation between chromosomes 9 and 22, and not through a simple deletion of chromosome 22 as was previously thought. Several investigators in the early 1980s showed that the Philadelphia chromosome translocation led to the formation of a new BCR/ABL1 fusion gene, composed of the 3'part of the ABL1 gene in the breakpoint on chromosome 9 and the 5' part of a gene called BCR in the breakpoint in chromosome 22. In 1985 it was clearly established that the fusion gene on chromosome 22 produced an abnormal chimeric BCR/ABL1 protein with the capacity to induce chronic myeloid leukemia.