In what could be claimed a major breakthrough, scientists have developed personalised blood tests for cancer, using whole genome sequencing .

A team at Johns Hopkins University has used data from the whole genome sequencing of cancer patients to develop individualised blood tests which they say can help physicians tailor patients' treatments.

According to the scientists, the genome-based blood tests, believed to be the first of their kind, may be used to monitor tumour levels after therapy and even determine cancer recurrence.

"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 cancer patient," lead scientist Victor Velculescu said.

For their research, the scientists scanned patients' genomes for alterations -- rearrangements of large chunks of DNA rather than changes in a single DNA letter among billions of others. They call their new approach Personalised Analysis of Rearranged Ends (PARE).

"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 tumour genome," co- scientist Bert Vogelstein said. "These alterations, like the reordering of chapters of a book, are easier to identify and detect in the blood than single-letter changes," he added.