Quest Diagnostics , the nation's leading provider of diagnostic laboratory testing, information and services, announced today that it has developed a new gene- based assay to help physicians identify metastatic Cancers of Unknown Primary origin (CUP). This laboratory-developed assay is currently available to physicians through Quest Diagnostics Nichols Institute, the company's esoteric testing laboratory, in San Juan Capistrano, California, which validated and introduced the test. The assay is based upon intellectual property licensed from Arcturus BioScience, Inc.

The CUP assay is intended to aid the physician in identifying the primary site of origin of Cancers of Unknown Primary for 39 tumor types, establishing prognosis, and determining appropriate therapy.

"Understanding where the cancer started is a vital piece of information for pathologists, oncologists and patients," said Joyce G. Schwartz, M.D., Vice President and Chief Laboratory Officer. "With information about the source of the cancer, physicians will be better able to determine prognosis and appropriate therapy. Earlier identification of the primary tumor could increase the odds of successful cancer treatment and overall survival."(1)

CUP refers to metastatic cancer in which cancer cells are found somewhere in the body, but the place of origin where they first started growing cannot be identified from physical examination, pathologic analysis or other forms of diagnostic testing. CUP is estimated to represent 3% - 15% of newly diagnosed cancers.(2) An estimated 70,000 new CUP patients are diagnosed each year and prognosis is typically poor.

The new test for Cancer of Unknown Primary will significantly reduce the amount of time it takes for pathologists and oncologists to assess CUP patients. Currently, without a true diagnostic for CUP, evaluating CUP patients using conventional diagnostic approaches based on imaging, biopsy, endoscopic and laboratory tests is a slow and costly process, typically taking several weeks or months and yielding limited success - identifying only 25% of primary cancers.(3) With the new CUP test, test results are available to physicians within two weeks.

The new CUP test uses gene expression profiling of biopsy tissue to determine the primary tumor site. Using the patient's biopsy specimen, gene expression profiles are generated for 92 genes using PCR methodology. The patient's gene expression profiles are compared to an in-house reference database comprising gene expression profiles from 39 known tumor types. Based on this comparison, the most likely site of origin is determined. Study results indicate that the test provides 82% sensitivity for identifying the site of origin in cancer of unknown primary and 99% specificity.(4)

For more information about the CUP test, physicians can call Nichols Institute toll-free at 1-800-642-4657, extension 2906.

About Quest Diagnostics

Quest Diagnostics is the leading provider of diagnostic testing, information and services that patients and doctors need to make better healthcare decisions. The company offers the broadest access to diagnostic testing services through its national network of laboratories and patient service centers, and provides interpretive consultation through its extensive medical and scientific staff. Quest Diagnostics is a pioneer in developing innovative new diagnostic tests and advanced healthcare information technology solutions that help improve patient care. Additional company information is available at: http://www.questdiagnostics.com/.

The statements in this press release which are not historical facts or information may be forward-looking statements. These forward-looking statements involve risks and uncertainties that could cause actual results and outcomes to be materially different. Certain of these risks and uncertainties may include, but are not limited to, competitive environment, changes in government regulations, changing relationships with customers, payers, suppliers and strategic partners and other factors described in the Quest Diagnostics Incorporated 2004 Form 10-K and subsequent filings.

   (1) Abbruzzese et al, J. Clin Oncol, (August) 1995:  pp 2094 - 2103
   (2) Ibid.
   (3) Ibid.
   (4) Erlander MG, Patel R, Raja R, et al.  Molecular classification of 39
       cancer subtypes with a gene panel:  implications for diagnosis of
       carcinoma of unknown primary.  Paper presented at :  11th Annual
       Meeting of the Association for Molecular Pathology, November 11,
       2005, Scottsdale, AZ.

SOURCE: Quest Diagnostics

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Web site: http://www.questdiagnostics.com/