The discovery of tiny particle-sized virus, called “exosomes,” shed by cancer in the blood stream, that comprises of entire genetic blueprint of cancer cells can make this idea possible.
By decoding this genomic data and looking for deletions and mutations associated with cancer, the research team believes this discovery could be translated into a test that helps physicians detect cancer and treat patients.
"At the present time, there is no single blood test that can screen for all cancer related DNA defects," said Kalluri, M.D., Ph.D., chairman and professor in MD Anderson's Department of Cancer Biology.
"In many cases, current protocols require a tumor sample to determine whether gene mutations and deletions exist and therefore determine whether the tumor itself is cancerous or benign. To procure tumor tissue, one needs to know that a tumor exists and if so, is it accessible for sample collection or removal? Finally, there are always risks and significant costs associated with surgical procedures to acquire tumor tissue," Kalluri said.
Initially, researchers were aware about these miniscule particles that existed carrying nucleic acids and proteins. An idea existed that exosomes carried small portions of the person's DNA.
However, upon further investigation, the MD Anderson research team was surprised to learn that the person's entire double-stranded genomic DNA spanning all chromosomes can be found in exosomes, including those mutated chromosomes that cause various cancers.
Furthermore, Kalluri and colleagues discovered that DNA derived from exosomes carried the same cancer-related genetic mutations, compared to the cancer cells taken from tumor.
Kalluri said: "Because different forms of cancer are associated with different chromosomal mutations, we believe analysis of exosome DNA taken from blood samples may not only help determine the presence of a cancerous tumor somewhere in the body but also identify mutations without a need for tumor sample.
"We also believe this ‘fingerprint’ will help lead us to the likely site of the tumor in the body. For instance, certain mutation spectrums would suggest pancreatic cancer or a brain-based tumor. While there is much more work to be conducted to develop such a test, having a tool such as this would increase our abilities to detect cancer in an earlier stage and therefore increase our chances of effective treatment.”
By Ruchi Singh
reporter
Park Sae-jin
swatchsjp@ajunews.com