MAbs for early detection of cancer

Dec 1 2009

Two sets of recommendations issued earlier this month have revised longstanding guidelines concerning the age at which women should first be tested for breast and cervical cancer and how frequently.

The US Preventative Services Task Force now recommends that routine screening mammography should begin at age 50 rather than 40, and that women ages 50 to 74 be tested every two years rather than one. Meanwhile, the American College of Obstetricians and Gynecologists recommends that Pap tests be administered no earlier than age 21, and then every two years to women between 21 and 29.

"Both of these recommendations have stirred intense debate because the benefits of mammograms and Pap tests are not black-and-white," says Amnon Gonenne, CEO of MabCure Inc., a biotechnology company that is developing novel diagnostics based on highly specific monoclonal antibodies (MAbs) for the early detection of cancer. "A decade ago or so, the medical community made specific recommendations for the use of these tests for the diagnosis of breast and cervical cancer. Now they have revised both guidelines based on accumulating evidence that the risks of these tests are greater than the benefits at an earlier age."

Some physicians have argued that there is potential for harm in overuse of Pap tests. The reason is that young women are especially prone to develop abnormalities in the cervix that appear to be precancerous, but that will go away if left alone. But when Pap tests find the growths, doctors often remove them, with procedures that can injure the cervix and complicate future pregnancy. Likewise, mammograms offer risks of their own, such as an increase in exposure to cancer-causing radiation.

"If you don't have a highly specific test offering a definitive diagnosis of 'cancer' vs. 'no cancer', you have to balance the upside of these tests (the chance of detecting cancer early ) and the downside of serious adverse reactions," says Gonenne. "This is where MabCure is heading—toward tests that can offer a definitive diagnosis of a given cancer."

MabCure's MAbs have been engineered with high specificity in order to detect cancer at an early stage, where the cure rates are greater than 90 percent. These MAbs are able to detect unique cancer markers, known as tumor-specific antigens, that appear to be present only on the surface of cancer cells but not in healthy cells. Presently, the company is developing MAbs that can test for the presence of ovarian and prostate, cancers in blood and urine. In addition Mabcure has developed Mabs against colon cancer and melanoma and plans to generate MAbs for breast cancer in the coming year.