Researchers identify genetic mutation responsible for most cases of Waldenstrom's macroglobulinemia

December 12, 2011

SAN DIEGO--Scientists at Dana-Farber Cancer Institute have identified a gene mutation that underlies the vast majority of cases of Waldenstrom's macroglobulinemia, a rare form of lymphoma that has eluded all previous efforts to find a genetic cause.

The research (abstracts 261, 300, 434 and 597), to be presented at the American Society of Hematology's 2011 annual meeting on Monday, Dec. 12 at 2:45 p.m. PST, points to an error in a single digit of DNA --¬ one of three billion letters in the human genetic code -- ¬as the leading culprit in Waldenstrom's, and a prime target for new therapies against the disease.

The discovery was made by sequencing the genome of tumor cells in Waldenstrom's patients, ¬ reading the cells' DNA letter by letter, ¬ and seeing where it differed from that of the patients' normal cells.

"We found that tumor cells in 90 percent of the patients we tested contained a single point mutation, an error in one of the bases that make up the 'rungs' of the DNA helix," says Steven Treon, MD, PhD, who led the research with his Dana-Farber colleague Zachary Hunter. "In subsequent experiments, when we treated the tumor cells with drugs that target the pathway activated by the mutated gene, the cells underwent apoptosis, or programmed cell death. These results suggest that new, effective treatments that target the tumor cells directly are now possible for people with the disease."

Waldenstrom's macroglobulinemia is a slow-growing form of non-Hodgkin lymphoma that originates in white blood cells known as B lymphocytes. When abnormal B cells begin to multiply out of control, they produce excessive amounts of a protein called monoclonal immunoglobulin, which causes the blood to thicken and flow less smoothly. In some patients, the disease produces no major symptoms; in others, problems can include weakness, fatigue, excessive bleeding, and weight loss. In severe cases, vision and neurological problems can occur. Approximately 2,000 to 3,000 people are diagnosed with Waldenstrom's each year in the United States; it is more common in men than women, more prevalent in people of Ashkenazi (Eastern European Jewish) descent, and arises more often in older people than young.

Although there isn't a cure for Waldenstrom's, treatments include drugs such as rituximab, bortezamib, and bendamustine. High-dose chemotherapy with autologous stem cell transplantation is infrequently also used. Since the disease was first described 70 years ago, all previous efforts to track down a genetic cause have been fruitless, Treon remarks. For the current research, Treon and his colleagues conducted whole genome sequencing of tumor cells and normal cells from 30 patients with Waldenstrom's. In collaboration with Complete Genomics of Mountain View, Calif., researchers "lined up" the sequences of the tumor and non-tumor cells to identify differences. Ninety percent of the tumor cells had a point mutation in the gene MYD88.

"The mutation causes the cells to produce a distorted protein, which switches on the IRAK complex pathway, leading to activation of NF-kB, a protein that is essential for the growth and survival of Waldenstrom's tumor cells," Treon comments. "When we shut down the pathway by blocking the abnormal protein with drug molecules, the tumor cells entered apoptosis." Equally important, the tested molecules had no adverse effect on normal cells.

The discovery of a genetic signature for Waldenstrom's will enable doctors to definitively determine which patients have the disease and not a similar condition such as other forms of lymphoma or multiple myeloma, Treon says. Drugs that block the abnormal protein or other proteins in the NF-kB pathway could, theoretically, short-circuit the disease process in many patients. Some of these drugs already exist, having been developed for other conditions. Treon and his colleagues are currently working to develop others and are testing them in experimental models.
Funding for the research was provided by the International Waldenstrom's Macroglobulinemia Foundation and the Bing family.

Dana-Farber Cancer Institute ( is a principal teaching affiliate of the Harvard Medical School and is among the leading cancer research and care centers in the United States. It is a founding member of the Dana-Farber/Harvard Cancer Center (DF/HCC), designated a comprehensive cancer center by the National Cancer Institute. It provides adult cancer care with Brigham and Women's Hospital as Dana-Farber/Brigham and Women's Cancer Center, and it provides pediatric care with Children's Hospital Boston as Dana-Farber/Children's Hospital Cancer Center. Dana-Farber is the top-ranked cancer center in New England, according to U.S. News & World Report, and one of the largest recipients among independent hospitals of National Cancer Institute and National Institutes of Health grant funding. Follow Dana-Farber on Twitter, @danafarber, and Facebook,

Dana-Farber Cancer Institute

Related DNA Articles from Brightsurf:

A new twist on DNA origami
A team* of scientists from ASU and Shanghai Jiao Tong University (SJTU) led by Hao Yan, ASU's Milton Glick Professor in the School of Molecular Sciences, and director of the ASU Biodesign Institute's Center for Molecular Design and Biomimetics, has just announced the creation of a new type of meta-DNA structures that will open up the fields of optoelectronics (including information storage and encryption) as well as synthetic biology.

Solving a DNA mystery
''A watched pot never boils,'' as the saying goes, but that was not the case for UC Santa Barbara researchers watching a ''pot'' of liquids formed from DNA.

Junk DNA might be really, really useful for biocomputing
When you don't understand how things work, it's not unusual to think of them as just plain old junk.

Designing DNA from scratch: Engineering the functions of micrometer-sized DNA droplets
Scientists at Tokyo Institute of Technology (Tokyo Tech) have constructed ''DNA droplets'' comprising designed DNA nanostructures.

Does DNA in the water tell us how many fish are there?
Researchers have developed a new non-invasive method to count individual fish by measuring the concentration of environmental DNA in the water, which could be applied for quantitative monitoring of aquatic ecosystems.

Zigzag DNA
How the cell organizes DNA into tightly packed chromosomes. Nature publication by Delft University of Technology and EMBL Heidelberg.

Scientists now know what DNA's chaperone looks like
Researchers have discovered the structure of the FACT protein -- a mysterious protein central to the functioning of DNA.

DNA is like everything else: it's not what you have, but how you use it
A new paradigm for reading out genetic information in DNA is described by Dr.

A new spin on DNA
For decades, researchers have chased ways to study biological machines.

From face to DNA: New method aims to improve match between DNA sample and face database
Predicting what someone's face looks like based on a DNA sample remains a hard nut to crack for science.

Read More: DNA News and DNA Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to