Scientists analyze genetic characteristics of cancers using multiple genomics technology platforms -
New research conducted by scientists affiliated partly UC San Francisco suggests that the one of 10 cancer patients will be diagnosed more accurately if their tumors were defined by cellular and molecular criteria rather than the tissue in which they originate, and this information, in turn, could lead to treatments most appropriate.
in the largest study of its kind to date, the scientists analyzed the molecular and genetic characteristics of more than 3,500 samples of tumors from 12 different cancer types using multiple technology platforms genomics.
cancers traditionally have been classified by their 'tissue of origin "-like breast, bladder or kidney cancer. But the tissues are composed of different types of cells, and new research indicates that, in many cases, the type of cells affected by cancer can be a useful guide to treatment than the tissue in which tumor originated.
the study, published August 7, 2014 publishing line of the cell was conducted under the initiative cancer genome Atlas (TCGA) conducted by the National cancer Institute and the National Institute for research on the human genome, both part of the National Institutes of Health.
in the new work, TCGA research network of scientists analyzed the DNA, RNA and proteins from tumor types 12 using six different genomic technologies to see how different tumor types compare to each other. The team arrived at a rating based on 12 sub-types of cancer. Five of them were consistent with classifications tissue of origin, but several newly identified subtypes were seen affecting a variety of fabrics.
"This genomic challenges not only our current system study cancer classification based on tissue type, but also provides a huge new resource data for further exploration, and a comprehensive list of features molecular distinguishing each of the newly described class of cancer, "said co-lead author Christopher Benz, MD, professor at the Buck Institute for research on aging, assistant professor of medicine at UCSF, and Helen Diller family member Comprehensive Cancer Center at UCSF.
particularly striking results were seen in cancers of the bladder and breast. At least three different subtypes of bladder cancer were identified, one virtually indistinguishable from lung adenocarcinomas, and another more similar to squamous cell cancers of the head and neck and lung. (In the new study, these squamous cell cancers seemed to form their own sub-type, whether they originate in the lung or head and neck.) The results may help explain why patients with bladder cancer "react often differently when treated with the same systemic therapy for their type of cancer apparently identical, "said Benz.
study also confirmed the known differences between the subtypes of breast cancer known as "luminal cancers" basal-like "and". But because the researchers compared these cancers not only with each other but with many other types of cancer, they were able to reveal that these differences are very deep, and basal-like breast cancers are their own distinct class. "What is amazing is that the basal breast cancer is also different from a luminal breast cancer as it is, say, kidney cancer," said co-lead author Denise Wolf, PhD, a researcher based at the Department laboratory medicine UCSF.
Commonly called "triple negative" basal-like cancers are aggressive, are more common in African American women and young women. "Although these basal-like cancers occur in the chest, at the molecular level, they have more in common with cancer and squamous cancers original than other subtypes of ovarian breast cancer," said co-author Christina Yau, Ph.D., a scientist Buck Institute's staff and assistant professor of surgery at UCSF.
TCGA was launched in 06 to compile genomic atlas more than 20 types of cancer. as the project progressed, however, the similarities between the types of cancer began to emerge, which led to the creation of TCGA project "Pan-cancer," the source of the data used in the new study.
"This is the first time you've been able to indicate important molecular features shared by the basal breast cancer, and cancer of the head and neck squamous and lung cancer," said Wolf. "And the same is true of immune activation, we found that different types of cancer have very similar immune signatures, a factor that may be clinically relevant with the rise of new immune therapies."
Benz thinks the number of patients eligible for reclassification will swell when multiple tumor samples and additional types of tumors are included in the next round of the Pan-Cancer project analysis, which should include more than 20 different types of tumors . "We'll just enjoy the tip of the iceberg when considering the potential of this type of multi-platform genome analysis," said Benz. "It could be up to 30 or 50 percent of cancers are reclassified."
Benz hope that these studies will feed into the design of clinical trials on genomics reclassification base tumors that patients become eligible for new therapies. "Although follow-up studies are needed to validate and refine the classification system of the newly proposed cancer," Benz said, "it will ultimately provide the biological basis for personalized treatment of the time cancer patients and clinicians look forward to. "
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