Stratagene has licensed for possible diagnostic development an 11-gene signature from the Sidney Kimmel Cancer Center that may predict tumor progression and metastasis, as well as identify so-called cancer stem cells.
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"Our plan is to use the sets of genes that have predictive capabilities for prostate and breast cancer to develop diagnostic test kits based on our proprietary quantitative PCR FullVelocity technology," said Joe Sorge, Stratagene CEO, in a statement. "These kits should enable the detection of cancer at an earlier stage than is now possible and guide doctors as they make therapeutic decisions to treat cancers."
Principal investigator Gennadi Glinsky and colleagues at the Sidney Kimmel Cancer Center developed the panel and studied it in 1,153 cancer patients diagnosed with 11 different cancer types. The panel, if validated through further research, has the potential to guide treatment, Glinsky told Pharmacogenomics Reporter. Patients with a poor prognosis could be treated aggressively with chemotherapy in early stage disease, he said. Should the survival likelihood of certain patients fall "as low as 10 to 20 percent" within a year or two, results from the genetic panel could be used to stratify them in clinical trials with experimental treatment.
Stem cells undergo assymetrical division, in which one of the two daughter cells is differentiated, while the other remains a stem cell. "The criteria for cancer stem cells would be this self-renewal ability, and the ability to generate tumors with very few cells" transplanted into a different animal, said Glinsky. "Only a small fraction of cancer cells recovered from a given tumor can maintain this function — most of the cancer cells constitute what we would say is differentiated progeny," which cease to proliferate after several divisions, he said.
Glinsky and colleagues identified the panel by comparing the genetic profiles of metastatic cancer stem cells with stem cells from mice lacking the function of the BMI gene. Without the BMI gene, stem cells are not capable of self-renewal, said Glinsky.
The SKCC team used an algorithm to reduce the number of genes to the smallest number necessary to identify the same samples, while still having human-gene orthologs, Glinsky said. "As soon as we found this set of genes, then we used this signature to query multiple human tumors, and basically asked the question whether different tumors — analyzed by taking samples from patients' bodies — would exhibit different profiles," Glinsky said.
Interestingly, metastatic tumors "tend to be the ones that resemble stem-cell-like profiles, and non-metastatic tumors do not," said Glinsky. The SKCC researchers found this to be true in prostate cancer initially, but "this rule holds for, to date, 11 different cancer types, including such diverse tumors as epithelial malignancy as well as non-epithelial cancers," he said.
"For non-epithelial cancers it was more or less anticipated because functional BMI in leukemia and leukemic stem cells is well documented and established," said Glinsky. "And now it seems that a similar pathway might be engaged in metastatic cancer diagnosed in multiple organ sites," he said.
The results suggest to Glinsky two pathways to cancer. The first is the "classical slow-progression model" with multiple mutational accumulation, while the second begins with stem cells or other early progenitor cells that begin with a self-renewal function and a "pre-wired ability to spread," he said. "And that's the one we have no ability to treat right."
Glinsky's SKCC group is trying to set up clinical trials of the panel "as early as this summer," at the Ordway Research Institute in Albany, NY, he said. With a multi-institutional, retrospective trial and a single-institutional prospective arm, the researchers hope to validate, with the Q-PCR format, that the technology works, "and then we will be able to define our ability to accrue and analyze patients about to undergo therapy," he said. If the two arms give satisfactory results, in as few as eight to 10 months from the start of the trial, "then we will be in a good position to go to the FDA and ask for approval for such a test," Glinsky added.
Stratagene could not be reached for comment before deadline.
— Chris Womack ([email protected])
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