Simple Blood Test May Soon Be Able to Diagnose Brain Tumors

In the U.S. today, approximately 360,000 people have brain cancer. In 2002, 40% of the 40,000 patients diagnosed with this disease died within one year. Brain tumors are the second leading cause of cancer-related deaths in children under the age of 20 as well as men under the age of 39. In women between 20 and 39, it ranks fifth in cancer-related deaths. In 2007, this meant 3,750 children under 20 were diagnosed with either a benign or malignant brain tumor and 70% of those were under the age of 15. In 2008, over 52,000 new cases are expected to be found. Additionally, of those with cancer elsewhere in their body, 100,000 patients are expected to see the cancer spread to their brain. Of those that survived their initial diagnosis in 1996, only 34% lived at least five years. Luckily, the survival rate has been steadily increasing from 21% in the 1970s to 31% in the 1990s. This is still abysmally low, however.

Patients Lose More than Their Health

The cost of this disease to its victims can be unrelenting. According to a study by the National Brian Tumor Foundation, of patients with brain cancer, 59% said their medical expenses were a financial hardship. Many families felt financially drained and had to borrow money (42%), increase their credit card debt (47%), accept a second or third mortgage (15%) or went completely bankrupt (7%). The cost of prescriptions, deductibles, increased insurance premiums and delayed disability funding exacerbated their medical costs and made expenses more difficult to pay. In fact, 15% of the patients assessed paid more than $1,000 each month for treatment. Making things more difficult, while 91% of patients were able to work before their diagnosis, only 33% were able to work afterwards. Furthermore, the disability insurance which was intended to help patients only makes things worse due to long, complicated forms that usually assure an initial denial. Even after acceptance, patients were required to wait two years before any benefits would take effect. During this interlude, patients were left to scrape by as best they could. Of the patients interviewed, 62% lacked disability insurance. The medical debt never failed to grow however, as it was found that a significant correlation existed between the time since diagnosis and the patient’s credit card debt.

Hope for Help in the Near Future

Brain cancer is notoriously difficult to diagnose and treat due to its location in the body. Usually, patients are forced to undergo invasive biopsy procedures for doctors to assess which type of cancer the patient has. This increases medical costs by increasing the time spent in the hospital during the operation and recovery, the drugs used for sedation and pain afterwards, and of course, the number of doctors required for such a procedure. However, it may soon be possible to find the same answers through a simple blood test.

Cancer cells, like other cells, “talk” to each other. Often a cell will accomplish this by secreting a protein that is recognized and acted upon by another cell. Cancer cells, for example, can send signals in this way to cause blood vessels to alter their normal route and instead, grow near the cancer cell. This redirection of blood vessels is what feeds the cell and allows it to grow. In cancer cells, these signaling factors are called microvesicles.

After the discovery of these signals as imperative for breast cancer cell growth, Dr. Johan Skog of Harvard Medical School began studying the microvesicles secreted by brain tumor cells. What turned this into a potential diagnostic method were the small bits of RNA found in the microvesicles. Previously, neither DNA nor RNA had been observed which made any diagnosis based on these signaling secretions impossible. However, when RNA was found, it opened the door to a blood-based genetic test. Skog and Dr. Xandra Breakefied, a neurologist also at Harvard Medical School, hypothesized that if the brain tumors were releasing signaling factors with RNA, they might be found in the blood where sensitive tests could detect them and distinguish between the types of brain cancers.

To test their idea, Skog and Breakefield collected the secretions from 30 tumors that had been frozen for long-term storage. They also examined blood samples from the same patients the tumors had been extracted from. In 28% of the blood samples, RNA from the microvesicles was found. In the tumors, RNA was found in almost 50%. Although this may seem to leave a lot of room for misdiagnosis, it is significant since RNA is very fragile and unstable and can degrade very quickly. The fact that RNA was found at all is rather amazing. It is believed that if these same tests were run on fresh samples, rather than those that had been frozen, a much higher number would test positive for the tumor-specific RNA. The RNA released from these tumors could even help doctors determine the genetic abnormalities of the cancer, allowing for a more tumor-specific therapy.

Although doctors do not expect this new method to completely replace the need for other diagnostic procedures, it could lend a way to extract valuable information in a relatively non-painful and inexpensive way.

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