THURSDAY, Jan. 20, 2005 (HealthDayNews) -- Harvard researchers have found a new marker that may signal more invasive and lethal forms of colon cancer.
These findings could eventually lead to more targeted treatments and new ways to screen for more aggressive disease, report the researchers.
"If patients had elevated levels [of the marker], their prognosis was significantly worse," said study co-author Richard Bates, an instructor of medicine at Harvard Medical School and Beth Israel Deaconess Medical Center.
During embryonic development and wound repair, the body normally undergoes a process called epithelial-mesenchymal transition (EMT), according to Bates. Occasionally, during EMT, epithelial cells can transform into tumor cells.
So, Bates and his colleagues induced EMT in colon cancer cells to see what differences they could find. They discovered that a molecule was expressed during EMT in the cancer cells. Because this marker is also released during wound repair, Bates explained, it was the levels of the marker that were critical, not its presence or absence.
The researchers then looked at samples from 488 human colon cancers, and found that elevated levels of the marker were associated with significantly reduced survival time. Those with high levels of the marker had an average survival rate of 4.8 years, while those with low expression of the marker survived an average of 16.5 years.
"This marker might be an attractive therapy candidate. It may be possible to design targeted therapy for invading or malignant tumors," said Bates. Also, he added, "if this marker shows up in early-stage tumors, we know those patients will be at far higher risk of developing metastatic disease and they can be treated more aggressively."
Bates added that because EMT only occurs during fetal development and wound repair, a treatment that interrupts the action of this marker would probably have few side effects.
"This is an interesting, but very preliminary, study," said Dr. Jay Brooks, chairman of hematology/oncology at the Ochsner Clinic Foundation Hospital in New Orleans. "This marker may help us tell patients early on which ones are at a higher risk of more serious disease and reoccurrence. And it may help us define which patients we may need to treat earlier, and which we may not need to treat right away."
But, he added, the difference in survival rates was not dramatic, and there wasn't information on what types of treatment each patient may have received, which could also affect survival rates.
Bates said what's most important for people to remember is that "early detection is best." And, he added, "We've just come across something that may make early detection even more important."
Results of the study appear in the Feb. 1 issue of the Journal of Clinical Investigation.
Colon cancer is America's fourth leading cancer killer, according to the National Cancer Institute. Each year, almost 105,000 people are diagnosed with colon cancer and more than 56,000 people die from the disease, according to the American Cancer Society.
Risk factors include being over 50, a family history of the disease, a history of polyps in the colon, or having ulcerative colitis or Crohn's disease. Studies also suggest that a poor diet and cigarette smoking may increase your risk of developing colon cancer.
More information
To learn about preventing colon and rectal cancer, go to the National Cancer Institute.
