Multiple myeloma is a type of plasma cancer that starts in the bone marrow. It is not a type of bone cancer.

Plasma cells are a type of white blood cells that play an important role in the immune system. They create antibodies that fight infections.

When multiple myeloma develops in the bone marrow, it makes it difficult for normal blood cells — white blood cells, red blood cells, and platelets — to form.

Although multiple myeloma starts in the bone marrow and can affect the bones, it is not a type of bone cancer.

This article reviews what kind of cancer multiple myeloma is, its possible causes and symptoms, and more.

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Multiple myeloma is a type of plasma cancer. It begins in the bone marrow, where white blood cells and other blood cells form.

As the cancer grows in the bone marrow, it can take away space from healthy blood cells, leading to low blood counts.

It can also cause issues with bone strength and density.

Bones have two kinds of cells that work together. Osteoclasts help break down old bone to make room for new bone development. Osteoblasts create the new bone. Typically, these cells work together to help bones grow and maintain bone density and strength.

Multiple myeloma interferes with the relationship between the two types of bone cells by telling osteoclasts to speed up their destruction of bone. This breakdown leads to low bone density and weak bones.

People with multiple myeloma have a higher risk of bone fractures because of weakened bones. This may lead some people to believe that multiple myeloma is a bone cancer, but it is not.

Learn more about multiple myeloma.

The exact cause of multiple myeloma is still unclear. Scientists do know it is the result of changes to either oncogenes or tumor suppressor genes in a person’s DNA.

Oncogenes help promote cell growth. Changes to these genes may cause plasma cells to grow uncontrollably. Early stages of multiple myeloma tumors often show changes to the MYC genes, while changes to RAS genes may be present after treatment. Both are types of oncogenes.

When multiple myeloma spreads to other areas of the body, changes to the p53 gene are often present. This is a type of tumor suppressor gene.

Dendritic cells in bone marrow produce interleukin-6 (IL-6), a hormone that stimulates growth of plasma cells. An abnormality in these cells that causes an excess of IL-6 may play an important role in the development of multiple myeloma.

The Centers for Disease Control and Prevention (CDC) note that the most important risk factor for multiple myeloma is age — it rarely appears in people under the age of 45 years.

Other possible risk factors include:

  • being male, as the condition is more common in males
  • being Black, as multiple myeloma occurs more often in Black people than in white people
  • experiencing exposure to X-rays or other radiation
  • having obesity or overweight

Learn more about the risk factors for multiple myeloma.

A person may not experience symptoms of multiple myeloma before diagnosis.

If symptoms do develop, they may include:

The symptoms are nonspecific, which means they may have a variety of underlying causes. It is best for a person to consult a doctor to determine the underlying cause.

Learn more about the symptoms of multiple myeloma.

A doctor may discover multiple myeloma during a blood or urine examination for an unrelated condition. A high level of protein in blood or urine can indicate this disease.

A doctor may order additional tests to confirm the diagnosis, including:

  • blood tests to check for abnormalities in proteins and the presence of certain antibodies
  • imaging tests such as:
    • X-rays
    • MRI
    • CT scan
    • echocardiogram
    • PET scan
  • core needle biopsy or fine needle aspiration biopsy

To receive a diagnosis of multiple myeloma, a person must have a plasma cell tumor or at least 10% plasma cells in the bone marrow, along with at least one of the following criteria:

  • 60% or more plasma cells in the bone marrow
  • high blood calcium levels
  • holes in bones from the tumor
  • significant anemia, or low red blood cell count
  • reduced kidney function
  • an increase in one type of light chain in the blood, with the one type being 100 times more common than the other

Possible treatments for multiple myeloma include:

  • chemotherapy
  • radiation therapy
  • stem cell transplantation with high dose chemotherapy
  • chimeric antigen receptor (CAR) T-cell therapy, typically for relapsed or refractory myeloma

Treatment cannot cure multiple myeloma, but it can help slow the progression of the disease and reduce a person’s symptoms.

A person can work with their doctor to determine the best treatment approach for them.

Learn more about treatments for multiple myeloma.

The following sections provide answers to frequently asked questions about multiple myeloma.

Are multiple myeloma and bone cancer the same?

Multiple myeloma is a type of plasma cancer. Plasma cells are a type of white blood cell. The cancer starts in the bone marrow and can cause weakened bones, but it is not a type of bone cancer.

What category of cancer is multiple myeloma?

Multiple myeloma is a type of plasma cancer. It is relatively rare. The National Cancer Institute (NCI) estimates that doctors will diagnose 35,730 new cases in the United States in 2023.

Is multiple myeloma a serious cancer?

Multiple myeloma is not a curable disease. The 5-year relative survival rate for multiple myeloma is 59.8%. The NCI estimates that 12,590 people will die as a result of multiple myeloma in 2023. This is 2.1% of all estimated cancer deaths for the year.

A relative survival rate helps give an idea of how long a person with a particular condition will live after receiving a diagnosis compared with people without the condition.

For example, if the 5-year relative survival rate is 70%, it means that a person with the condition is 70% as likely to live for 5 years as someone without the condition.

It is important to remember that these figures are estimates. A person can consult a healthcare professional about how their condition is going to affect them.

Was this helpful?

Multiple myeloma is not a bone cancer. It is a type of plasma cancer that starts in the bone marrow.

As it progresses, it can cause the bones to lose density and break more easily, among other issues. This may lead some people to believe it is a type of bone cancer.

Treatment focuses on helping to slow the progression of the disease and prevent or reduce the severity of symptoms.

It is best for a person to contact a doctor as soon as they have concerns about multiple myeloma. The doctor can order various tests to confirm the diagnosis and advise on suitable treatments.