Focus on Lymphoma
Network - Fall 2010
We asked Fredrick Hagemeister, M.D., professor in the Department of Lymphoma and Myeloma, about lymphomas, promising new treatments for this group of cancers and how
MD Anderson’s Lymphoma Tissue Bank is making a difference in research.
What are lymphomas?
Lymphomas are cancers of the body's lymphocytes, a type of white blood cell of which there are both B cells and T cells. After these cells become malignant (cancerous), they can invade other organs.
B cell lymphomas are relatively common in the United States and Europe, but have many different ways of appearing in patients, and are classified by their appearance under the microscope. They may occur in the young and the old, and depending on their genetic makeup, can be fast- or slow-growing; many of them can be cured with chemotherapy, with or without radiotherapy.
T cell lymphomas are relatively uncommon in the United States, and are more difficult to control than are B cell lymphomas, making the distinction between these two large categories important for decisions regarding therapy.
What causes them?
We’re not yet sure, but we suspect that some forms of lymphoma may have a genetic disposition, not in terms of inheriting the disease, but perhaps in inheriting a type of immune deficiency, for example. Other possible causes include environmental factors, such as exposure to pesticides and herbicides, and certain viruses, although these causes are rare.
What’s the difference between Hodgkin’s and non-Hodgkin’s lymphomas?
All subtypes of classical Hodgkin’s lymphoma exhibit a specific type of abnormal cell called a Reed-Sternberg cell which should be present in correct combinations with other non-cancer cells in order for a pathologist to call the disease Hodgkin’s lymphoma.
On the other hand, non-Hodgkin’s lymphomas have a wide variety of different cells present, and usually most of the cells in a patient’s tissue biopsy consist of these malignant cells, which have specific proteins on the surface of these cells that help in naming them. There are over 30 types of non-Hodgkin’s lymphomas, and some grow slowly, whereas others grow rapidly.
Why should lymphoma patients have their slides reviewed by a doctor trained in hematopathology?
An expert hematopathologist — a physician who has experience in the microscopic classification of lymphomas — should review the pathologic slides of each lymphoma patient. There are more than 20 types of T cell lymphomas alone, and many more types of B cell lymphomas, and determining the exact diagnosis may be crucial in making a difference in a patient's outcome.
What types of targeted therapies are being used to treat both Hodgkin’s and non-Hodgkin’s lymphomas?
One promising area is in the development of targeted therapies like proteasome inhibitors, which work without damaging a person's DNA. Instead, they block the proteins that DNA produces. Proteasome inhibitors affect malignant cells, so they die, but healthy cells are not as significantly affected.
Other new drugs, including monoclonal antibodies and immunomodulatory agents, also have great potential to improve the lives of lymphoma patients. Monoclonal antibodies attach primarily to proteins on the surface of cancer cells and cause an immune response against these cells, while immunomodulatory agents tend to affect many of the normal cells surrounding the cancer cells, such as tumor blood vessels, to block their growth.
Why is MD Anderson’s Lymphoma Tissue Bank so important?
At MD Anderson, lymphoma patients have the option to donate part of their biopsies to the Lymphoma Tissue Bank, which is housed here. It's been in operation about 2-1/2 years, and our research effort is really expanding.
For example, Sattva Neelapu, M.D., in our department has recently identified an important protein that causes immune suppression by preventing antitumor cells from killing cancer cells in tissues of patients with lymphomas that were stored in the tissue bank. Based upon this finding, we were able to begin a trial with the support of the National Cancer Institute to test an antibody that is designed to stop the immune suppression and therefore allow the antitumor cells kill the tumor cells in patients with these diseases. Furthermore, these new antibodies that are designed to stop the immune suppression are much less toxic to other normal cells in the human body.
Someday, we may be able to cure patients without the harsh effects of chemotherapy, and funding of studies like those being conducted by Dr. Neelapu would not be possible without our tissue bank.
In another study, we have tested a new drug on tissues stored in the tumor bank, and have found this drug to be highly effective in certain kinds of lymphomas, and not others.
With what we’re learning, researchers hope to advance treatment of the disease and help patients live longer. Using the donated tissue, they’ll study how lymphoma develops and try new drugs on tissue samples before testing them in people. This will allow drugs with the best chance of success to be moved rapidly from the laboratory to the clinic for the benefit of patients.