In 2002, Emanuel Petricoin, Ph.D. published a provocative paper in The Lancet describing the application of proteomics in ovarian cancer. Despite the media reports that a new technology and screening test would be available by the end of 2002 for ovarian cancer, both the work and controversy continue.
Proteomics is the study of proteins and protein fragments. Instead of measuring a single protein, such as the CA-125, proteomics looks at the pattern of proteins. As noted earlier, the CA-125 test is not particularly accurate in detecting early-stage ovarian cancer. Proteomics is expected to determine the pattern of proteins for ovarian cancer [among other cancers] and become a detection tool in diagnosing early stage disease and therefore, positively impacting a patient’s prognosis. Additionally, the hope is that the use of proteomics can also detect very early recurrence of ovarian cancer.
The History
In research on proteomics, administering a test that can be completed in 30 minutes using blood that can be obtained from a finger stick, researchers were able to differentiate between serum samples taken from patients with ovarian cancer and those from unaffected individuals. The research, a joint effort between the FDA/NCI Clinical Proteomics Program and Correlogic Systems Inc., unites two exciting disciplines: proteomics - the study of the proteins inside cells - and artificial intelligence computer programs.
The diagnostic test relied on software that is able to detect patterns of key proteins in the blood. Using a sophisticated artificial intelligence computer program developed by Correlogic, scientists were able to "train" the computer to distinguish between patterns of small proteins found in the blood of cancer patients vs. control samples. The artificial intelligence program identified a pattern consisting of only a handful of proteins, among thousands, that could be used to distinguish between women with ovarian cancer and women with non-cancerous conditions.
The scientists first used serum samples from known cancer patients and unaffected individuals to establish proteomic patterns which were present at different levels in the two groups. Once these patterns were identified, the researchers compared them with the patterns of the same proteins in serum samples from other patients with and without cancer. The researchers correctly identified 50 out of 50 cancers and 63 of 66 non-cancer samples. An important finding was the ability to correctly identify, in a small sample of patients, all stage I ovarian cancer cases. The authors of the paper caution that further study is needed to confirm the sensitivity and accuracy of this technique as a diagnostic tool. They hope that by combining the proteomic approach with other methods of ovarian cancer diagnosis, such as ultrasound, its accuracy can be further improved.
Correlogic Systems
Correlogic Systems is a private company which is developing a screening tool for the early detection of epithelial ovarian cancer – even in its earliest and most curable stages. Initially, the test will be used by physicians for assessing high-risk women. The test will be marketed under the name OvacheckTM and requires only a blood draw. This test applies the technology of proteomics – measuring the pattern of proteins for ovarian cancer and any related changes.
When OvacheckTM will be available depends on the FDA. If the FDA determines that OvacheckTM may be offered as a regulated lab test, then it can be available shortly after regulatory determination. If the FDA decides that the test requires full regulatory submission, it may be months or longer. Additionally, Correlogic Systems has five medical institutions currently participating in continued research on OvacheckTM.
NCI/FDA
The NCI/FDA researchers are continuing to improve the performance of proteomic analysis for ovarian cancer. It is the position of the NCI/FDA that validation in a very large clinical trial is needed before a commercial test should be available. Elise Kohn, at the NCI is currently recruiting ovarian cancer patients in remission to determine the effectiveness of proteomics vs. the single protein biomarker, the CA-125. Additionally, Kohn is working with the Gynecologic Oncology Group [GOG] to assess the proteomic tool used alone or in combination with current screening methods. The NCI/FDA scientists are exploring many patterns of proteins as well as other technology to determine the most effective approach for clinical implementation.
Parts of the above information were reprinted, courtesy of the National Cancer Institute
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