Fusion gene

An article about fusion genes in genetics

Overview

A fusion gene is a hybrid gene formed from two previously separate genes. It can occur as a result of chromosomal rearrangements such as translocation, interstitial deletion, or chromosomal inversion. Fusion genes are often associated with cancer and can be used as biomarkers for diagnosis and treatment.

Formation

Fusion genes are typically formed through the joining of two separate genes, which can occur through various mechanisms:

• Translocation: A segment of one chromosome is transferred to another chromosome.
• Inversion: A segment of a chromosome is reversed end to end.
• Deletion: A segment of a chromosome is lost, and the remaining parts are joined together.

These events can lead to the creation of a new gene with novel functions, which can contribute to the development of diseases such as cancer.

Role in Cancer

Different types of gene fusions.

Fusion genes are frequently found in various types of cancer. They can lead to the production of abnormal proteins that drive the growth and proliferation of cancer cells. Some well-known examples include:

• BCR-ABL: Found in chronic myeloid leukemia (CML), resulting from a translocation between chromosomes 9 and 22, known as the Philadelphia chromosome.
• PML-RARA: Associated with acute promyelocytic leukemia (APL), resulting from a translocation between chromosomes 15 and 17.

These fusion genes can serve as targets for specific targeted therapies, such as tyrosine kinase inhibitors in the case of BCR-ABL.

Detection and Diagnosis

Fusion genes can be detected using various molecular biology techniques, including:

• PCR: Amplifies specific DNA sequences to detect the presence of fusion genes.
• FISH: Uses fluorescent probes to visualize specific DNA sequences on chromosomes.
• NGS: Allows for comprehensive analysis of genetic alterations, including fusion genes.

These techniques are crucial for the accurate diagnosis and classification of cancers, as well as for guiding treatment decisions.

Therapeutic Implications

The identification of fusion genes has significant implications for the development of targeted therapies. Drugs that specifically inhibit the activity of proteins produced by fusion genes can be highly effective in treating certain cancers. For example, imatinib is a drug that targets the BCR-ABL fusion protein in CML, leading to improved patient outcomes.

Related pages

• Oncogene
• Tumor suppressor gene
• Chromosomal translocation
• Cancer genomics