What is multiple myeloma?
Multiple myeloma is a disease of the immune system. The cells that normally make antibodies, which are proteins that bind to germs, those are called plasma cells. In multiple myeloma these plasma cells grow unrestricted and they make too much antibody protein.
Why is that bad?
That is bad because the antibody protein circulates in the bloodstream and it causes problems with the kidneys and other organs. The ... plasma cells, they grow too much and they crowd out the normal cells in the bone marrow. Normally, the plasma cells only occupy about 5 percent of the cells in the bone marrow. In multiple myeloma, it’s much higher. It can get greater than 20 percent. In can be 100 percent. So the cells of the immune system that make too much protein, not only are they making too much protein, but the plasma cells are growing in an unrestricted way.
So they’re bigger?
No, they’re not bigger. They resemble normal plasma cells. But there are just too many.
So they grow in number?
Cancer is cells that grow and don’t stop growing. Normally, when cells grow they touch each other and when they touch each other, that sends a signal to stop the growth. What happens in any cancer is the cells don’t pay attention to that. They grow unrestricted and make tumors. Same thing with multiple myeloma. The malignant cell is the cell of the immune system called the plasma cell and this grows too much. It doesn’t stop growing. It ends up occupying most of the bone marrow. When it does that, it crowds out the other cells of the bone marrow. Usually people have low white cell count and low red cell count and low platelet count because the plasma cell is squeezing out all the normal cells of the bone marrow.
The word ‘grow’ is confusing. Do they get bigger?
Maybe a better word to use instead of grow is divide. They divide. Instead of one cell just staying put, one cell will divide into two cells, and then it will continue to divide. It grows, meaning divide.
Normal cells will divide also, right? But they divide in a more restricted way?
Controlled. They stop when they touch each other. What happens in cancer is that feedback mechanism doesn’t work. They don’t stop dividing. That causes a lump, a tumor.
On the spectrum of common or rare cancers, is this more to the common side?
It’s more common. It’s seen frequently.
Men more than women?
It’s similar, and as someone gets older the incidence increases. I’ve seen it in people in their 20s and it can occur at any age. It’s more common in people older than 60.
The other unique feature of MM is it affects the bones. Myeloma, for some reason, causes holes in the bones. It can cause problems with the bones, where people have pains in the bones, bones can fracture. The classic presentation of somebody with MM is they present with back pain because of the bones being weak, and the red cell count is low. That’s called anemia.
It has this characteristic protein in the blood. So there is a specific blood test that can be done to look for evidence of too much of this protein of the immune system. That’s what clues us into multiple myeloma.
So let's go back. MM is a blood cancer in the bone?
It’s a cancer of the blood in the bone marrow. There’s a proliferation of these cells of the immune system called plasma cells. And they start occupying a good part of the liquid center of the bone, the bone marrow. But the unique feature of multiple myeloma is that it makes too much of a protein that circulates in the blood and can cause problems with organs.
In leukemia, what happens is the leukemic cells grow in the bone marrow but they spill out in the bloodstream and it causes white cell count to go high. In multiple myeloma, the plasma cells do not spill out in to the bloodstream. Only the protein.
Some people don’t have symptoms, some people have a lot?
People who have full-blown MM usually have symptoms. They’ll either have bone pains or they’ll be fatigued because their red cell count is low. They’ll have anemia. That causes fatigue. The other thing that happens, because it affects the bones, it can cause the calcium from the bones to be high in the bloodstream and that can cause you to be confused and sleepy and it can affect the kidneys. That’s somebody with full-blown myeloma. There are disorders that are not really myeloma but could turn into myeloma where you just detect the protein in the blood stream but the bone marrow is normal. That happens a lot. … Sometimes when you detect this protein in the blood, you’re not sure whether that’s all there is to it or that’s the tip of the iceberg of a full-blown multiple myeloma. So you have to do a bone marrow aspiration and biopsy and X-ray the bones and see if there are other features of multiple myeloma.