Cancers - Types: June 2012

Tuesday

Do we know what causes Waldenstrom macroglobulinemia?

Do we know what causes Waldenstrom macroglobulinemia?

Scientists have made great progress in understanding how certain chan ges in DNA can cause normal lymphocytes to become lymphoma or multiple myeloma cells. They are
also beginning to understand how chan ges in the DNA of some lymphomas cause their
cells to produce high levels of IgM, which causes most of the symptoms of Waldenstrom
macroglobulinemia (WM).
DNA is the chemical that carries the instructions for nearly everything our cells do. We
resemble our parents because they are the sour ce of our DNA. But DNA affects more
than the way we look. Some genes (parts of our DNA) contain instructions for controlling
when cells grow and divide. Certain gen es that promote cell division are called
oncogenes . Others that slow down cell division or cause cells to die at the right time are
called tumor suppressor genes .

We know that cancers can be caused by DNA mutations (defects or changes) that turn on oncogenes o r turn off tumor suppressor genes. Some people with certain types of cancer have DNA changes they inherited from a parent, which increased their risk for the disease. Researchers are stud ying families that have many cases of WM to try to find the gene that may cause this disorder in some people. Many changes in DNA have been found in WM cells. These DNA changes are usually acquired after birth (not passed on from a parent). Acquired changes may result from exposure to something in the environment, such as radiation or cancer-causing chemicals.
Often these changes o ccur for no app arent r eason. Ever y time a cell prepares to divide
into 2 new cells, it must duplicate its DNA. This process is not perfect and sometimes
copying errors o ccur. Fortunately, cells have repair enzymes that "proofread" DNA. But
some errors may slip past, especially if the cells are growing rapidly.
Human DNA is packaged in 23 pairs of chromosomes. Sometimes, a piece of a
chromosome is missing - this is called a deletion . The most common defect seen in WM
is a deletion of part of chromosome 6. Another type of chromosome defect in WM is
called a translocation. In a translocation, a piece of one chromosome becomes attached to
a different chromosome. Chromosome changes like these can cause oncogenes to be
turned on or tumor suppressor genes turned off.

Researchers have found that some patients with WM have important chan ges or defects
in other bone marrow cells. These changes may also cause excess growth of the cancer
cells. Certain cells in the bone marrow called d endritic cells release a hormone called
interleukin-6 (IL-6) that helps normal plasma cells and plasmacytoid lymp hocytes grow.
Excess IL-6 p roduction by these cells appears to be an important factor in the
development of WM.

What are the risk factors for Waldenstrom macroglobulinemia?

What are the risk factors for Waldenstrom macroglobulinemia?

A risk factor is anything that affects your chance of getting a disease su ch as cancer.
Different can cers have different risk factors. For example, unprotected exposure to strong
sunlight is a risk factor for skin cancer. Smoking is a risk factor for man y cancers.
Researchers have found a few risk factors that make a person more likely to develop
Waldenstrom macroglobulinemia (WM). But most people with these risk f actors nev er
develop the disease. Even if a patient with WM does have one or more risk factors, it is
impossible to know for sure how much that risk factor contributed to causing the cancer.

Monoclonal gammopathy of undetermined significance
Monoclonal gammopathy of und etermined significance (MGUS) is an abnormality of
antibody-producing cells that is related to multiple myeloma and WM. In MGUS, like
WM and multiple myeloma, abnormal cells in the bone marrow make a large amount of
one particular antibody -- this is called a monoclonal gammopathy . As long as the patient
has no problems from the abnormal cells or the antibody, it is called MGUS . Generally,
the abnormal cells in MGUS make up less than 10% of the bone marrow and the amount
of abnormal protein in the blood is not very high (<3g/dl). In most cases, MGUS causes
no health problems, but up to 25% of people with MGUS will go on to be diagnosed with
a cancer o r related seriou s health problem (like multiple myeloma, WM, another
lymphoma, or amyloidosis) over the 20 years after diagnosis.
Age
The risk of Waldenstrom macroglobulinemia goes up with age. It is rare among people younger than 50 years old.
Race
Waldenstrom macroglobulinemia is more common among whites than among African Americans. In contrast,
multiple myeloma is about twice as common among African Americans as white
Americans. The reasons for these differences are not known.
Sex
Men are more likely than women to develop this disease.
Heredity
Genetic factors may play a role. In one study, about 5% of patients with WM had a close
relative with the disease, and another 15% of WM patients had a relative with another
type of lymphoma.
Hepatitis C
A recent study has shown that people with chronic hepatitis C infection develop WM
more than twice as often as people without the virus.

What are the key statistics about Waldenstrom macroglobulinemia?

What are the key statistics about Waldenstrom macroglobulinemia?

Waldenstrom macroglobulinemia (WM) is very rare, with an incidence rate of about 6
cases per million people per year in the United States. About 1,000 to 1,500 people are
diagnosed with WM each year in the United States.
It is almost twice as common in men as it is in women, and is rare among African
Americans. There are few cases of WM in younger people, but the chance of developing
this disease increases as people age. About 7 in 10 cases of WM ar e diagn osed in those
over the age of 65.

Cells responsible for Waldenstrom macroglobulinemia

Cells responsible for Waldenstrom macroglobulinemia

WM is a cancer o f B cells. The cancer cells in people with WM are similar to those of 2
other types of cancer: multiple myeloma and non- Hodgkin lymphoma. Multiple myeloma
is considered a cancer of plasma cells and non-Hodgkin lymphoma is a cancer of
lymphocytes. WM cells have features of both plasma cells and lymphocytes and are
called lymphoplasmacytoid. These cells produce large amounts of an abnormal type of a
certain antibody protein (immunoglobulin M, or IgM) that causes many of the symptoms
of WM, including excessive bleeding, problems with vision, and nervous system
problems.

Monday

What is Waldenstrom macroglobulinemia

Waldenstrom macroglobulinemia (WM) is a type of non-Hod gkin lympho ma (NHL) that
produces large amounts of an abnormal protein (called a macroglobulin ). Another name
for WM is lymphoplasmacytic lymphoma. This condition used to be called
Waldenstrom's macroglobulinemia , so some people refer to it as Waldenstrom's .
The lymphoma cells in WM grow mainly in the bone marrow, where they can crowd out
the normal cells that make the different blood cells. This can lead to low levels of red
blood cells (called anemia ), which can make peop le feel tired and weak. It can also cause
low numbers of white blood cells, which makes it hard for the body to fight infection.
The numbers of platelets in the blood can also drop, leading to increased bleeding and
bruising.
Lymphoma cells can also grow in organs like the liver and spleen, causin g these organs
to swell, leading to abdo minal pain. The macroglobulin made by the lymp homa cells can
cause other problems as well.