The Science Behind Multiple Myeloma Disparities

Medically Reviewed by Brunilda Nazario, MD on April 07, 2022
4 min read

Every year, scientists learn more about multiple myeloma, a type of  blood cancer that starts in your bones. They’re working to figure out what causes this cancer and why some groups have a higher chance of getting it. Their discoveries have led to new treatments and could help find a cure one day.

Although it’s a small overall percentage of cancer cases, multiple myeloma has an outsized impact on the Black community. This group is twice as likely to get the illness, and die from it. It also affects Black Americans at a younger age.

Despite these challenges, Black people diagnosed with multiple myeloma tend to have a less serious form of the disease. And when they have equal access to treatment, this group lives just as long as, or even longer than, other races and ethnicities.

Multiple myeloma is a complex illness. It differs from person to person, and there are 10 subtypes. Also, each person usually has around four slightly different kinds of it. These change as the illness advances and doctors treat it.

There’s no clear answer to why multiple myeloma affects the Black community more often than others. “It’s somewhat of a mystery,” says S. Tariq Mahmood, MD, a board-certified hematologist and medical oncologist at Atlanta Cancer Care.

With certain cancers, scientists have discovered a clear-cut link to our actions. For example, we know that smoking causes most lung cancers. But with multiple myeloma, “There’s not something that someone typically does that results in them having this cancer,” Mahmood says. 

Scientists are looking into the connection between multiple myeloma and health-related causes like carrying extra weight. But they need to do more research. Around 40% of Black men and 56% of Black women over age 20 have obesity in the U.S.

As researchers continue to look at multiple myeloma, they’re uncovering other possible reasons why Black people are more likely to have this type of cancer.

Researchers have studied multiple myeloma in families dating back to the 1920s. Over the decades, they’ve identified dozens of families in which more than one member has myeloma or other cancers of the plasma cells. This suggests that when a close blood relative like a brother, sister, or parent has the disease, you’re also more likely to have it. The link may be even stronger within Black families.

It’s possible to pass some other types of cancers to your children through your genes. Researchers have linked cancers of the breast, ovaries, pancreas, and prostate to the faulty BRCA1 and BRCA2 genes.

Your chances of getting multiple myeloma may rise when a family member has it. But “as of right now, we haven’t identified any gene that’s passed on from family member to family member,” Mahmood says.

Researchers are also looking at whether you can pass a type of protein called paratarg-7 through your family line. It’s an important sign of multiple myeloma that’s found more often in Black people with the disease. In one multiple myeloma study, nearly 30% of Black people carried the protein.

Pinpointing genetic ties to multiple myeloma can help researchers create targeted treatments for the disease.

Before a doctor diagnoses you with multiple myeloma, you may have a different yet connected condition. Monoclonal gammopathy of undetermined significance, or MGUS (pronounced "EM-guss"), is a noncancerous condition that can evolve into myeloma. Researchers have discovered that if you’re Black, you’re twice as likely to have MGUS.

Myeloma happens when cancer-causing white blood cells (plasma cells) build up in your bone marrow and overtake healthy cells. This leaves you vulnerable to infection, since normal plasma cells make antibodies that pinpoint and attack germs.

The cancerous plasma cells create monoclonal proteins, or M proteins. These abnormal antibodies can build up in your body and lead to problems with your bones, kidneys, and immune system. If doctors discover high M protein levels in your blood, it’s a telltale sign of multiple myeloma.

M proteins are also a sign of MGUS. The difference is that the proteins are at lower levels, and MGUS doesn’t harm you.

At one point, everyone who has active myeloma also had MGUS. But having MGUS doesn’t always mean you’ll get myeloma.

People living with MGUS don’t need treatment, but a blood cancer doctor (hematologist or oncologist) will watch you over time for any changes.