Specific protein may help predict cancer spread
February 1st, 2011
12:19 PM ET

Specific protein may help predict cancer spread

If a tumor has high levels of a certain enzyme or protein, it could tell doctors if the cancer will spread,  at least in some cancers, according to very early research published Tuesday.

Researchers at the National Institutes of Health and in Hong Kong tested tumors from two completely different types of cancer: liver as well as pheochromocytoma and paragangliomas, which are rare forms of adrenal cancer.  When they tested for the presence of a new form of the protein carboxypeptidase E called CPE-delta N, they found patients whose tumors had high levels of CPE-delta N were more likely to have their cancers spread to other parts of the body.

"If you can identify a patient in the early stages [of cancer] who's at high risk for progression of disease, one can modify their therapy," says Dr. Stephen Hewitt, a staff scientist at the National Cancer Institute and one of the study authors.

It's important to emphasize that this is still very early research. "This test is not something that patients can go and obtain through other sources at this time," says Hewitt. That's because more research and clinical trials with many more patients are needed to verify what these researchers have found in the small groups of patients studied so far.

For example, researchers report on a group of 18 patients with stage 2 liver cancer. "These patients will normally be told by their physicians that their cancers are not likely to recur and they do not receive further treatment after the surgery" says Y. Peng Loh, a senior investigator at the Eunice Shriver National Institute of Child Health and Human Development. Loh explains when these patients' tumors were tested for CPE-delta N, 5 had very high levels of the protein and in 4 patients the cancer was found to have spread 2 years after their surgery. She suggests the test that was used to determine these protein levels can better predict the aggressiveness of a tumor and help researchers determine which patients need to be more closely watched after surgery.

Dr. Karel Pacak, also of the Eunice Shriver National Institute of Child Health and Human Development, looked at the rare adrenal cancers pheochromocytoma and paraganglioma. He says they can be very dangerous because they release excess amounts of epinephrine and norepinephrine - hormones that regulate heart rate and blood pressure. "These hormones can be truly devastating to our patients because they are affecting many organs and especially cardiovascular systems."  Pacak says many of these patients may end up with heart attacks, stroke or severe or lethal irregular heartbeats. When researchers looked at tumors from 14 patients with these rare cancers, they found that the cancer spread in all of the patients with very high levels of CPE-delta N.  Those with low levels did not see their cancer metastasize.  Pacak is convinced larger clinical trials with more patients will confirm the results of this study.

This isn't the first biological marker that was found to predict cancer spread, but the others didn't pan out. Hewitt says the testing in this study was very rigorous and he believes since the biomarker was found in two completely different types of cancer, "that may be something that separates this biomarker from many of the other biomarkers that were previously identified, which are usually in a single tumor."

The researchers hope more research on this enzyme will lead to the development of treatments to block CPE-delta N to prevent cancer from spreading in future patients.

The study published in the Journal of Clinical Investigation.

soundoff (One Response)
  1. Bill

    Step by step, ever so slowly gains are being made in the treatment of cancer. Maybe some day the word 'cure' will be used for all cancers. Right now early detection the best we have. However, many people could save or extend their lives if they would just get tested for prostate, cervical, breast, colorectal etc. cancers and they don't do it. Why they do not do it is a mystery to me.

    A PSA saved my life.

    February 1, 2011 at 16:19 | Report abuse | Reply

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