T(15;17)

T(15;17) is a specific type of chromosomal translocation often associated with acute promyelocytic leukemia (APL). This translocation involves the swapping of genetic material between chromosome 15 and chromosome 17, resulting in a fusion gene known as PML-RARA.

Overview

In normal cells, the PML gene on chromosome 15 and the RARA gene on chromosome 17 each have distinct functions. The PML gene is involved in cell growth and division, while the RARA gene is involved in the regulation of gene expression. However, in cells with the T(15;17) translocation, these two genes are fused together. This fusion gene produces a new protein that can disrupt normal cell growth and differentiation, leading to the development of APL.

Acute Promyelocytic Leukemia (APL)

Acute promyelocytic leukemia is a subtype of acute myeloid leukemia, a cancer of the blood-forming tissue (bone marrow). In normal bone marrow, hematopoietic stem cells produce red blood cells (erythrocytes), white blood cells (leukocytes), and platelets. In APL, however, the bone marrow produces too many immature white blood cells, called promyelocytes. These abnormal cells can crowd out the healthy cells, leading to anemia, infection, and easy bleeding.

File:Acute Promyelocytic Leukemia.jpg

Micrograph showing acute promyelocytic leukemia, characterized by abnormal promyelocytes.

Diagnosis and Treatment

The diagnosis of APL typically involves blood tests, bone marrow examination, and genetic testing to identify the T(15;17) translocation. The presence of the PML-RARA fusion gene is a definitive diagnostic marker for APL.

Treatment for APL often involves chemotherapy and a class of drugs known as retinoids, which can induce the abnormal promyelocytes to mature into normal white blood cells. In some cases, stem cell transplantation may be considered.

See Also

• Chromosomal translocation
• Acute myeloid leukemia
• Gene expression
• Hematopoietic stem cell