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Proteins may warn of colon cancer growth

Researchers have identified six proteins seen only in colon cancer cells, which may serve as markers to warn when cancer growth begins.

The finding is based on research into a little-understood structure that exists in every cell _ the nuclear matrix. The nuclear matrix is a protein structure that seems to act as a scaffolding, supporting and controlling the nucleus where the chromosomes and the genes they carry reside.

It is now known that when normal cells become cancerous, the nuclear matrix gets changed and new types of proteins are made. Also, the new proteins seem to be specific for each type of tumor. So far, different sets of tumor-specific proteins have been identified for breast, bone and prostate tumors.

Ying-Jye Wu, vice president for research at Matritech Inc., a biotechnology company in Cambridge, Mass., and three colleagues reported on the newly discovered colorectal cancer proteins Tuesday in the Proceedings of the National Academy of Sciences.

The team already is working on ways to detect the new proteins in blood, hoping to find a simple, powerful diagnostic test that catches cancer early.

"We expect to be able to detect it (colorectal cancer) in the polyp stage," before the tumor becomes malignant, Wu said.

If the research holds up, he said, it offers "an excellent monitoring system" for colorectal cancer.

The American Cancer Society estimates there will be 149,000 new cases of colorectal cancer in the United States in 1994, causing about 56,000 deaths. If the cancer is detected early, about 90 percent of the patients live five years or more, but for patients whose tumor cells have spread, the survival rate is less than 7 percent.

The new research is important because a major problem with most cancers is early detection. If tumors aren't discovered early enough, they can evolve and metastasize, sending out deadly "seeds" to take root elsewhere in the body. These secondary tumors are often what kill the patient.