Wrapping our Heads Around Leukemia – The Latest Research

2009-06-22 | |
Last updated: 2009-06-22

When the majority of us are told of someone who has leukemia, we immediately recognize that this person has a cancer of the blood. What fewer of us know, however, is that leukemia is actually the name of a group of cancers that affect different groups of people, different types of blood cells in the body and at present, have very different survival rates following diagnosis and treatment. There are in fact, four different major types of leukemia that themselves can be further broken down. In particular, the four types are called Acute Lymphocytic Leukemia (ALL), Acute Myelogenous Leukemia (AML), Chronic Lymphocytic Leukemia (CLL), and Chronic Myelogenous Leukemia (CML).

leukemia blood cells

All of these cancers except ALL are mostly experienced by adults. ALL, however is mostly seen in young children, but is also sometimes seen in those over 65 years of age. The ALL and CML types of cancer are now highly treatable with 85-90% of those who receive treatment surviving more than 5 years following diagnosis. The exception is that ALL in adults is not as readily treated. In contrast, at the other end of the spectrum, AML, the most common form of adult leukemia, is a much less treatable form of blood cancer with only 40% of patients who receive treatment surviving beyond 5 years. One of the factors that makes AML so hard to treat is that a number of different chemically-based dysfunctions can result in the same condition.

With so many variations of leukemia, there are quite a number of directions in which researchers are headed in their attempts to understand the different forms of the disease and how best to treat each of them. In fact, progress is being made in understanding and better treating all forms of leukemia whether to further increase already reasonably successful treatments like those of ALL and CML or in the case of CLL and AML to seriously reduce the rate of mortality.

ALL Advances

Some of the latest research directed toward ALL is coming as a result of efforts to better understand the genetic factors affecting the disease and its treatment. One important finding made by researchers at St. Jude Children’s Research Hospital has been the identification of specific mutations in the leukemia cells that can be used to predict the likelihood of the disease to return following treatment. This finding is valuable because it allows doctors to determine the most effective course of treatment for a given person based on their genetics. In addition, it also allows doctors to limit the use of radiation treatment to only those patients with more aggressive forms or return of the cancer.

In related efforts, researchers at Paterson Institute for Cancer Research have found a reason as to why one of the key ALL anti-cancer drugs is less effective in some patients. The researchers found that some of the patients have leukemia cells containing proteins that break down the cancer drug used to actually treat the leukemia. The discovery is very helpful because it tells the researchers that they must now work to modify the drug such that it is less susceptible to being broken down instead of doing its work to promote the death of the cancerous cells.

CML Advances

While the prognosis for most CML patients is good with the existing treatments, some 10% do not improve. One important finding from the Cancer Therapy & Research Center (CTRC) at The University of Texas Health Science Center at San Antonio has been a means of identifying the mutated stem cells growing within the bone marrow that will turn into the mature cancerous white blood cells associated with this type of leukemia. The identification of these stem cells is valuable because although current drugs might effectively kill the cancerous white blood cells, the survival of the stem cells means that the disease has not been eradicated and will return.

CLL Advances

Thought of as a leukemia that is incurable with known techniques, CLL is generally a slow progressing disease, but one form of CLL is very aggressive with rapid progression. Because of these variations of the condition, it is difficult to determine how best to treat patients. That being said, some research results from UC San Diego School of Medicine are promising because they suggest a way to tell the difference between the more rapidly developing form of the cancer and forms that develop more slowly.

In particular, the researchers found that higher levels of a specific enzyme in the blood were indicators of the more aggressive form of the disease. These results are useful in two ways: first in that the optimal therapy can be determined based on the type of CLL a patient has and second, researchers now have a new area of investigation to create drugs that will lower these blood enzyme levels and possibly aid in causing the death of the leukemia cells.

AML Advances

As the least effectively treated form of leukemia at the present time, research directed toward understanding AML is crucial. One finding of interest from The University of Texas M. D. Anderson Cancer Center has been the identification of a means for preventing growth of leukemia cells by deactivating the cell’s ability to respond to natural growth-promoting chemicals. These results are promising because they suggest a means of at least halting the growth of the tumors associated with this form of leukemia. The findings were positive enough that the drug developed to prevent the tumor growth is moving to initial drug trials.

General Leukemia Advances

While specific research is currently targeted directly at many of the individual forms of leukemia, some interesting research results have come that affect all forms of leukemia. One interesting finding from the University of California, San Francisco has been the identification of the gene that controls the rate of the stem cell production within the bone marrow. These stem cells can become any form of blood cell so a defect or absence of the gene controlling the cell growth rate can result in various forms of leukemia. The research result is very important because it means that the key to treating many forms of leukemia could be related to developing drugs to kill the mutated stem cells.

As a final valuable research result, the same work from St. Jude Children’s Research Hospital on ALL has determined a means of chemically identifying the number of remaining cancerous cells following treatment. This determination of a means to measure what is called minimal residual disease (MRD) is incredibly valuable to patients because it allows the doctors to directly measure how effective a treatment has been and whether additional treatments are required. Without this ability to measure chemically, doctors must wait following treatment and visually inspect the blood cells to make a determination of the success of treatment. With the new approach, the wait can be eliminated and patients can be treated before the disease returns.

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Category: Medical Research

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