Rosetta Genomics last week said that it plans to launch a blood-based miRNA diagnostic for colon cancer in 2010.
The company also reported initial clinical efficacy data for the test, dubbed miRscreen Colon, which shows that the expression patterns of two miRNAs can be used to identify the presence of the disease with 91 percent sensitivity and 72 percent specificity.
Rosetta and its collaborators "have, for the first time, identified in serum potential miRNA biomarkers of colorectal cancer," Aaron Ciechanover, chairman of Rosetta's scientific advisory board, said in a statement. "If treated early, 90 percent of colon cancer patients survive. The … impact of an effective, non-invasive colon cancer-screening test cannot be overstated."
According to data presented by Rosetta last week at the American Society of Clinical Oncology's 2009 Gastrointestinal Cancers Symposium, the company set out to evaluate the presence of miRNAs in the sera of colorectal cancer patients and controls, and to determine whether the serum levels of certain of these non-coding RNAs differ between the two groups.
In their experiments, Rosetta and collaborators extracted total RNA from serum samples taken from 52 people with colorectal cancer and 81 healthy individuals. They successfully extracted miRNAs from 96 percent of the samples.
Using proprietary, semi-high-throughput qRT-PCR process, levels of 363 miRNAs were measured in sera from 10 healthy controls and 10 colorectal cancer patients, according to the poster.
This analysis revealed "significant differential expression of 11 microRNAs," an expression pattern the investigators also detected in a cohort of 118 patients and controls, the poster states.
In the end, "a combination of two particular miRNAs could be used to identify colorectal cancer patients with 91 percent sensitivity and 72 percent specificity" — numbers that are "comparable" with the performance characteristics of currently used colorectal cancer-screening tests.
Specifically, colorectal cancer patients were found to have lower levels of hsa-miR-16 and hsa-miR-125b, the poster notes.
In light of these data, "circulating microRNAs represent promising candidates for robust, sensitive, and easily accessible screening tests" for colorectal cancer, the poster concludes.
Though miRscreen Colon is expected to be Rosetta's first test that analyzes miRNA expression patterns in biofluids, similar tests are under development, Rosetta Chief Commercialization Officer Ronen Tamir told RNAi News this week.
"We believe that our platform is so sensitive that it can be translated from one substance to another," he said. "So far, [in] any type of body fluid we looked at – serum, saliva, whole blood, peripheral blood – we found microRNAs."
Rosetta has declined to disclose details about these other tests, including their indications and possible commercialization dates. However, Tamir noted that in future tests, the specific biofluid used will in part be linked to the disease for which a patient is being screened.
Not Alone
While Rosetta appears poised to be the first to market with a biofluid-based miRNA diagnostic, the company isn't the only group pursing the approach. For instance, in July, researchers from the Fred Hutchinson Cancer Research Center reported in the Proceedings of the National Academy of Sciences that miRNAs are present in human plasma "in a remarkably stable form that is protected from endogenous RNase activity."
"MiRNAs originating from human prostate cancer xenografts enter the circulation, are readily measured in plasma, and can robustly distinguish xenografted mice from controls," the team wrote in the paper's abstract. "This concept extends to cancer in humans, where serum levels of miR-141, an miRNA expressed in prostate cancer, can distinguish patients with prostate cancer from healthy controls."
And in October, investigators from Nanjing University published data in Cell Research showing that miRNAs obtained in serum could be used to distinguish healthy individuals from those with lung cancer, colorectal cancer, and diabetes.
That same month, a team from Ohio State University published a paper in Gynocologic Oncology detailing the differential expression of eight miRNAs found in sera obtained from ovarian cancer patients and healthy controls.
"We demonstrate that the extraction of RNA and subsequent identification of miRNAs from the serum of individuals diagnosed with ovarian cancer is feasible," the Ohio State researchers wrote.
On the commercial side, Exiqon President and CEO Lars Kongsbak told RNAi News in late December that his company expects to begin offering miRNA profiling services using blood and serum sometime this year (see RNAi News, 12/11/2008).
"There is no doubt that big universities have a significant need for outsourcing profiling," he said at the time. Meanwhile, pharmaceutical firms are increasingly interested in exploring the potential of miRNAs as biomarkers for monitoring disease progression or for patient stratification in clinical trials, he added.
And in 2007, Asuragen, which was the first to commercialize a miRNA-based diagnostic with a test that differentiates pancreatitis from pancreatic ductal adenocarcinoma (see RNAi News, 4/24/2008), presented data showing that it could isolate and quantify miRNAs from biofluids such as serum, plasma, urine, and saliva.
Asuragen CEO and CSO Matt Winkler this week declined to discuss his company's activities regarding miRNA analysis from body fluids. Officials from Exiqon were not available for comment.