Let's Talk About Multiple Myeloma Causes
Who gets this blood cancer and why is the million dollar question—and unfortunately, we still don’t have the million dollar answer on that. But certain factors can raise your risk. Here's what you need to know.
Among the many frustrating things about the blood cancer known as multiple myeloma is the fact that it’s hard to predict who will get it. Sure, scientists know some of the risk factors, but most people who develop the disease don’t even have a family history. That said, there are several things that boost a person’s chances of developing the disease—and understanding what they are can help you take action if you ever notice symptoms.
Our Pro Panel
We went to some of the nation's top experts in multiple myeloma to bring you the most up-to-date information possible.
Cindy Varga, M.D.
Medical Oncologist, Assistant Professor
Tufts Medical Center, Tufts University School of Medicine
Myo Htut, M.D.
Associate Clinical Professor of Hematology
City of Hope Comprehensive Cancer Center
Faisal Saghir, M.D.
Hematologist and Medical Oncologist
Northwestern Medicine Kishwaukee Hospital
No, at least not yet. But it is treatable. Many new treatments have been discovered in the last decade, and some doctors are starting to call it a “chronic” condition that can be managed successfully for years.
Yes. Multiple myeloma used to be known as Kahler (or Kahler’s) disease. It was named after Otto Kahler, the doctor who first discovered it in 1889. Other names for multiple myeloma are myelomatosis and plasma cell myeloma.
There is no single gene that causes multiple myeloma. But changes in certain genes in blood plasma cells over a person’s lifetime are linked to the disease. Specifically, changes in specific oncogenes that trigger cell growth (MYC and RAS) and tumor suppressor genes (p53) that slow cell growth are correlated with multiple myeloma.
Yes. Men are at a higher risk of developing the disease than women, and African Americans are twice as likely to get MM as white Americans. African Americans account for about 20% of multiple myeloma cases, even though they make up only 13 percent of the overall population in this country.
What Is Multiple Myeloma, Again?
Multiple myeloma (MM) is a type of blood cancer. It happens when certain white blood cells known as plasma cells mutate and start growing out of control. People with MM develop tumors in their bone marrow, sometimes in more than one spot.
As these tumors take up more and more space inside the bones, they keep the healthy marrow from doing its job of making infection-fighting white blood cells and red blood cells, which carry oxygen around the body.
Multiple myeloma is a pretty rare disease—the average American’s risk of getting at some point is just one in 132. (Compare that with the number of women who will develop breast cancer, which is one in 12.) About 30,000 cases of MM are diagnosed every year, and there are an estimated 130,000 people living with it in the U.S. today.
The disease has no cure, but multiple myeloma treatment improves every year. Today, the average five-year survival rate (defined as the percentage of people who live at least five years after diagnosis) is over 50%. The 5% of people with MM who are diagnosed at early stages have an even better outlook—for those folks, the 5-year survival rate is over 70%.
So, What Causes Multiple Myeloma?
All cancers begin the same way: A rogue cell begins to morph and multiply in ways it’s not supposed to. In multiple myeloma, blood cells known as plasma cells start to grow out of control. Exactly what triggers these cells to turn cancerous isn’t well understood, but doctors have pinpointed possible genetic components to the disease—plus some other factors that slightly increase risk.
Is Multiple Myeloma Genetic?
No, and yes. Sort of. It’s not “genetic” in the same way that breast cancer can be, for example. In breast cancer, if your parent passes down particular gene mutations like BRCA1 and BRCA2, your odds of breast cancer go up exponentially. There is no inheritable gene mutation for multiple myeloma.
But multiple myeloma is genetic in the sense that the genes contained in your DNA play a pretty big role in raising your risk of the disease.
Here’s how it works:
Your DNA contains genes that tell cells in your body how to behave.
“Oncogenes” trigger cell growth, while “tumor suppressor genes” slow it down or cause old and damaged cells to die off.
If there are mistakes or mutations in your DNA, it can turn these genes on or off, potentially leading to multiple myeloma.
Research suggests that the most likely cause for MM is random mutations in these genes that happen during a person’s lifetime.
Studies in MM patients have pinpointed abnormalities in specific genes, including MYC oncogenes in plasma cells, RAS genes in bone marrow cells, and changes in p53 tumor suppressor genes that may allow the cancer to spread.
Another component of our DNA, called chromosomes, may also play a role. Normal human cells have 46 chromosomes. But multiple myeloma cancer cells are often found to have an extra chromosome or may be missing a part of one chromosome.
In about half of MM cases, there’s also a mix up in which part of one chromosome has switched with another part and is arranged out of order, a phenomenon called translocation. If this mix up happens next to an oncogene, it can switch it “on” and trigger cancer cell growth.
Does Family History Play a Role?
Family history may be a factor for some people. Even though researchers have not found a specific multiple myeloma gene or mutation that you can inherit from your parents, multiple myeloma does seem to run in some families. So, if you have a parent or sibling with MM, you have a slightly higher-than-average risk of the disease, too.
Is Age a Multiple Myeloma Risk Factor?
Age is a strong predictor of multiple myeloma risk, possibly because it can take decades of little gene mutations to accumulate before one finally tips the balance and triggers plasma cells to become cancerous.
In fact, 96% of cases are diagnosed in people over 45 years old, and more than 63% of cases are in people over 65. Fewer than 1% of diagnoses happen in people under 35.
Does Race or Gender Make a Difference?
Men are more likely to develop MM than women. And research shows that African Americans are about twice as likely to get multiple myeloma than white Americans: About 20% of the estimated 30,000 Americans living with multiple myeloma today are African American, even though they make up just 13% of the overall U.S. population. Rates of MM are lowest in people of Asian and Pacific Islander descent.
Another way to look at it: In the United States, the annual incidence of multiple myeloma is 16.3 cases per 100,000 in black men, 11.9 cases in black women; 8.1 in white men and 4.9 in white women; 8.2 for men of Hispanic descent and 5.5 for women; 4.9 in Asian or Pacific Islander men and 3.0 in women.
Excess Body Fat Is a Risk Factor
Having a BMI in the overweight category (25.0 to 29.9) or obese category (30.0 and above) is linked with an increased risk of developing multiple myeloma. Doctors aren’t sure exactly why, but emerging research suggests that fat cells within the bone marrow may encourage the growth of myeloma cancer cells.
Other Blood Conditions Are Linked to MM
All plasma cells in the blood produce antibodies that help fight infection. But when plasma cells start to mutate and turn into myeloma cells, they can no longer make these healthy antibodies. Instead, they produce something called “monoclonal protein” or “M protein.”
People who are found to have a small amount of M protein in their blood are said to have “monoclonal gammopathy of undetermined significance,” or MGUS. People with MGUS have a 1% to 2% chance of going on to develop multiple myeloma or another blood cancer, such as lymphoma.
Does Smoking Cause Multiple Myeloma?
Smoking is known to be a cause of 13 different types of cancer, including a blood and bone marrow cancer called acute myeloid leukemia. But studies have not (yet) linked smoking with an increased risk of multiple myeloma.
Does Benzene Cause Multiple Myeloma?
Benzene is a chemical that is widely used in pesticides, plastics, rubbers, dyes, and detergents. It’s also found in cigarette smoke and the exhaust of gas-powered cars. It’s known to cause bone marrow and blood cancers, specifically leukemia and acute myeloid leukemia. Studies have also linked benzene to multiple myeloma, but the evidence isn’t as strong.
Understanding Multiple Myeloma Risk Factors
The important thing to remember is that even though you don’t have control over things like gender and race, there are a few risk factors for multiple myeloma that you do have the ability to change, like your weight. Regular exercise (aim for 30 minutes a day, five days a week) and eating a healthy diet (high in fresh fruits and vegetables, low in saturated fat) can make a positive impact in lowering your risk for multiple myeloma.
And if you already have the disease and are wondering how you got here, rest assured that no one single thing you did (or didn’t do), has caused you to have MM. The reasons some people get it and some people don’t is still unknown. But regardless, if you have multiple myeloma the best news of all is that new and better treatments for it are being developed at this very moment.
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- Benzene and Multiple Myeloma: American Cancer Society. (2020). “Benzene and Cancer Risk.” cancer.org/cancer/cancer-causes/benzene.html
- Multiple Myeloma and Smoking: The National Cancer Institute. (2020). “Harms of Cigarette Smoking and Health Benefits of Quitting.” cancer.gov/about-cancer/causes-prevention/risk/tobacco/cessation-fact-sheet