NCCN Guidelines for Patients® | Multiple Myeloma - page 11

9
NCCN Guidelines for Patients
®
Multiple Myeloma, Version 1.2014
1
About multiple myeloma
What are M-proteins?
What are M-proteins?
Normal antibodies are made of two heavy protein
chains and two light protein chains.
See Figure 1.4.
Heavy chains are one of five forms—A, D, G, E, or
M. And light chains are one of two forms—kappa or
lambda. The form of heavy chain present defines the
type of antibody. Most people with myeloma—about
60 out of every 100—have myeloma cells that make
G antibodies.
The antibodies made by myeloma cells aren’t normal.
They are called monoclonal proteins or M-proteins
because they are an excess of one type of antibody.
M-proteins are made uncontrollably and not in
response to a specific germ in the body. They don’t
help to fight infections.
In most patients, myeloma cells make very large
amounts of M-proteins. Rarely, people with
myeloma have few or no M-proteins. This is called
oligosecretory or nonsecretory myeloma.
As shown in
Figure 1.4
, myeloma cells also tend
to make more light chains than needed to form a
complete M-protein. These are called free light chains
because they aren’t attached to a heavy chain as
in a normal antibody. High levels of free light chains
are found in the urine of most people with myeloma
(75 out of every 100 people). In about 20 out of
100 people with myeloma, the myeloma cells only
make free light chains and no complete M-proteins.
Doctors call this light chain myeloma or Bence Jones
myeloma.
Figure 1.4
Antibodies made by a
plasma cell versus a
myeloma cell
Illustration Copyright © 2014 Nucleus Medical Media, All rights reserved.
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