NEW YORK (Reuters Health) – New research suggests that B-cell clones may be a useful early marker for chronic lymphocytic leukemia (CLL) since they are found in nearly all patients years before the diagnosis is made.

In The New England Journal of Medicine for February 12, Dr. Ola Landgren, from the National Cancer Institute, Bethesda, Maryland, and colleagues note that the presence of small numbers of B-cell clones in the peripheral blood, referred to as monoclonal B-cell lymphocytosis, has been linked with CLL. It was unclear, however, whether patients with CLL always have monoclonal B-cell lymphocytosis first.

To investigate, the research team analyzed data from 45 participants in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial who were diagnosed with CLL up to 6.4 years after enrollment. Flow-cytometric and molecular analysis were used to test for B-cell clones.

Overall, 44 of the 45 patients (98%) had a B-cell clone prior to diagnosis, according to the report.

Immunoglobulin heavy-chain variable (IGHV) genes could be identified and analyzed in 35 of the patients. Among the clones were 16 IGHV3 genes and 9 IGHV4 genes. Twenty-seven of the IGHV sequences contained mutations.

“A better understanding of monoclonal B-cell lymphocytosis and monoclonal gammopathy of undetermined significance through prospective studies like the one by Landgren et al. should open new doors to the detection, assessment, treatment, and prevention of B-cell lymphoid cancers,” note editorialists Dr. Robert F. Vogt, Jr. from the Centers for Disease Control and Prevention, and Dr. Robert A. Kyle, from the Mayo Clinic, Rochester, Minnesota.

N Engl J Med 2009;360:659-667,722-723.