According to a recent article published in the journal Blood, measuring gene expression through microarray analysis offers great accuracy in providing a specific leukemia diagnosis.
Leukemia is a cancer that affects cells in the blood and bone marrow. There are several different classifications or types of leukemia, as well as specific subtypes within each classification. Subtypes are based on the type of cells that are cancerous, specific genetic alterations within a cell, the way a cell looks under a microscope, as well as levels of other blood cells. All of these factors are indicative of the general clinical course of the leukemia; standard therapeutic approaches are established for the different classifications of this disease. Since the type of therapy chosen for treatment of leukemia is highly dependent upon the specific classification of leukemia, an accurate and precise diagnosis is imperative to provide optimal outcomes.
The measurement of gene expression, or activity of a gene, has emerged as a novel approach in the diagnosis and assessment of response to therapy. This process is referred to as gene expression profiling. Gene expression profiling in the clinical setting for several types of cancer is only beginning to be utilized. OncoType DX™ is one such test measuring gene expression in early breast cancer. Numerous clinical trials are underway evaluating gene expression profiling in various other diseases as well.
Researchers from Germany recently conducted a study to evaluate gene expression profiling in the diagnosis of leukemia. The study included over 900 blood or bone marrow samples from patients who had been diagnosed with several different types of leukemia. Using gene expression profiling, leukemia subtypes were accurately identified in over 95% of samples. Specific types of leukemia were identified with 100% accuracy in some types of acute myeloid leukemia (AML), chronic lymphatic leukemia (CLL), and pro-C-cell acute lymphoblastic leukemia (pro-B-ALL).
The researchers concluded that gene expression profiling provides high accuracy in the identification of subgroups of leukemia. Further studies in the evaluation and improvement of the use of gene expression profiles for the accurate diagnosis of leukemia are warranted. Patients diagnosed with leukemia may wish to speak with their physician about their individual risks and benefits of participating in a clinical trial further evaluating gene expression profiling. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (www.cancer.gov) and www.cancerconsultants.com.
Reference: Haferlach T, Kohlmann A, Schnittger S, et al. Global approach to the diagnosis of leukemia using gene expression profiling. Blood. 2005; 106: 1189-1198.