Toronto, Oct 8 : For the first time, scientists have decoded the entire genome of a patient''s metastatic breast cancer-a breakthrough towards creating personalized cancer therapies using a patient''s genetic information.

The achievement could change how people think about the way cancer develops and provides new insights into which drugs could benefit patients the most.

"I''m excited by the possibilities. In fact, I never thought I would see in my professional lifetime that it would become possible to routinely sequence genomes in the way that we''re now doing," The Globe and Mail quoted Samuel Aparicio, the head of the department of breast and molecular oncology at the B. C. Cancer Agency and one of the lead scientists involved with the discovery, as saying.

While decoding the metastatic breast-cancer genome, which contains all of the genetic information of a patient''s cancer, scientists could identify all of the mutations in the tumour- a feat that has never before been accomplished.

After identifying all of the tumour mutations of the developed cancer - a total of 32 were found - scientists had the information to look back and see which of those mutations were present in the patient''s original, primary tumour.

They discovered that only 11 of the 32 mutations were present in the original tumour, with only five of those present in all of the original cancer cells, which means that even in the early stages, cancer cells aren''t uniform.

This proves that even from the outset, cancer cells contain different mutations, which change over time.

"I think we''re getting used to the idea an individual patient''s cancer is itself multiple individual cancers that may behave differently," said Aparicio.

Aparicio said their work could help usher in a new era in which scientists will be able to decode cancer genomes in all patients to help create therapies targeted to the mutations present in their tumours.

The findings of the study are published in the journal Nature. (ANI)