Personalized blood tests for cancer using whole genome sequencing have been developed by Johns Hopkins Kimmel Cancer Center scientists.

Data from the whole genome sequencing of cancer patients was used by Boffins to develop individualized blood tests they believe can help physicians tailor patients'' treatments. The genome-based blood tests, believed to be the first of their kind, may be used to monitor tumor levels after therapy and determine cancer recurrence.

 Victor Velculescu, M.D., Ph.D., associate professor of oncology and co-director of the cancer biology program at Johns Hopkins said," We believe this is the first application of newer generations of whole-genome sequencing that could be clinically useful for cancer patients.Using this approach, we can develop biomarkers for potentially any ancer patient."

 February 24 issue of Science Translational Medicine published a report on the work, according to which the scientists scanned patients'' genomes for alterations that, they say, most researchers have not been looking for - rearrangements of large chunks of DNA rather than changes in a single DNA letter among billions of others. The new approach is called Personalized Analysis of Rearranged Ends (PARE) by them.

Bert Vogelstein, M.D., Clayton Professor of Oncology, co-director of the Ludwig Institute at Johns Hopkins, and Investigator in the Howard Hughes Medical Institute, says," In sequencing individuals'' genomes in the past, we focused on single-letter changes, but in this study, we looked for the swapping of entire sections of the tumor genome. These alterations, like the reordering of chapters of a book, are easier to identify and detect in the blood than single-letter changes."

The Johns Hopkins team used next-generation sequencing methods to catalogue the genome sequence data of each patient, using six sets of cancerous and normal tissue samples taken from four colorectal and two breast cancer patients,. To find DNA rearrangements, the team first identified regions where the number of DNA copies was more or less than anticipated and where sections of different chromosomes fused together. To identify DNA sequences displaying incorrect ordering, orientation, or spacing, these regions were further analyzed. (With Input from Agencies)