VOA常速英语:New Vaccine A Possible Hope For Brain Cancer Patients

People with glioblastoma, an aggressive form of brain cancer, survive for only fifteen months on average after diagnosis. But now there may be hope for those battling this deadly disease. Researchers at Duke University say they have a new vaccine that can curb the growth of this cancer and extend lives.  In clinical trials, the vaccine has shown positive results in fighting the tumors, raising hopes for patients and scientists.

Karen Vaneman was diagnosed with glioblastoma two years ago. After going through surgery, chemotherapy, and radiation, she participated in the clinical trial of a brain cancer vaccine at Duke University Medical Center.

More than two years have passed, and doctors say she is beating the odds.   Patients with glioblastomas usually die within 15 months after diagnosis.

Dr. John Sampson at the Duke University Medical Center says the vaccine works by targeting a protein present in several types of cancers. "The most amazing thing that we have seen with this drug is we have a number of patients now who are surviving five years or more without any evidence of tumor recurrence," he said.

Dr. Sampson says survival rates with glioblastoma are normally poor because some cancer cells in the brain respond to treatments and others don't. "While one cell may be susceptible to chemotherapy and another susceptible to radiation, there may be a third cell that is susceptible to neither of those standard therapies," he said.

Dr. Markus Bredel at Northwestern University analyzes the genetic makeup of brain tumors, specifically gene mutations in glioblastomas. He is trying to understand what causes brain tumors. "The difficult question is which of those many, many genes are actually important in the disease process and which are just simply bystanders to the process," he said.

Researchers say the brain cancer vaccine also works by making the immune system produce antibodies that attack cancer cells.  "The idea here is to sort of expose the tumors' vulnerabilities and really educate the immune system to attack these tumors more specifically," Sampson said.

In the United States there are about 10,000 new cases of glioblastoma every year.

While the news on clinical trials is positive, experts also caution that challenges remain in developing the vaccine during an economic downturn.

"The problem really is how do you develop the drugs in a business climate when economy is not so great. The reality is that it's just an unfortunate situation. And hopefully as the economy improves and investments into drugs for patient populations like brain cancer become more viable, companies will start investing again," Sampson said.

The National Cancer Institute says brain tumors rank among the top causes of cancer deaths in the United States.