Protein map of human spit created

By Julie Steenhuysen

CHICAGO (Reuters) - U.S. researchers have identified all 1,116 unique proteins found in human saliva glands, a discovery they said on Tuesday could usher in a wave of convenient, spit-based diagnostic tests that could be done without the need for a single drop of blood.

As many as 20 percent of the proteins that are found in saliva are also found in blood, said Fred Hagen, a researcher at the University of Rochester Medical Center in New York who worked on the study.

"This is potentially a large field that has many clinical implications in the area of disease diagnostics," said Hagen, whose work was published in the Journal of Proteome Research.

The researchers hope saliva-based tests could be used to diagnose cancer, heart disease, diabetes and a number of other conditions.

"To be able to diagnose disease using saliva, you really have to have a comprehensive understanding of the saliva proteome," Hagen said in a telephone interview.

Like a genome, which lists all of the genes in an organism, a proteome is a complete map of proteins. While genes provide the instruction manual, proteins carry out the instructions by regulating cellular processes.

Researchers from five universities -- the University of Rochester, The Scripps Research Institute, the University of Southern California, The University of California San Francisco and the University of California Los Angeles -- sought to determine the complete set of proteins secreted by the major salivary glands.

BLOOD, SPIT AND TEARS