Nine in 10 men with advanced prostate cancer have genetic mutations in their tumors that could be targeted by either existing or new chemotherapy drugs, according to a landmark new study.

American and British scientists have mapped the genetic mutations in life-threatening tumor cells that have spread to other parts of the body — calling the initiative a prostate cancer “Rosetta Stone.”

The researchers say doctors can immediately begin testing for these mutations and give patients with advanced prostate tailor-made cancer treatments that target them, Medical Xpress reports.

"We have for the first time produced a comprehensive genetic map of the mutations in prostate cancers that have spread round the body,” said Johann de Bono, an oncology specialist with the Institute of Cancer Research, London, and the Royal Marsden NHS Foundation Trust, which led the research.

“This map will guide our future treatment and trials for this group of different lethal diseases. We're describing this study as prostate cancer's Rosetta Stone because of the ability it gives us to decode the complexity of the disease, and to translate the results into personalized treatment plans for patients.”

The study, which involved researchers from eight academic clinical trials centers around the world, involved analysis of large numbers of samples of metastatic cancer tumors from hospitals in the U.S. and U.K. — including those from patients with drug-resistant cancers.

The researchers assessed the genetic codes of metastatic tumors from the bone, soft tissues, lymph nodes, and liver of 150 patients with advanced prostate cancer.

The findings, published in the journal Cell, indicated nearly two thirds of the men had mutations in a molecule that interacts with the male hormone androgen which is targeted by current standard treatments — potentially opening up new avenues for hormone therapy.

Mutations in the BRCA1 and BRCA2 genes — tied to breast cancer, and effectively by drugs called PARP inhibitors — were found in nearly 20 percent of patients.

The scientists also discovered new mutations, never detected before in prostate cancer but common to other cancers, in the so-called PI3K and RAF gene families. These can be targeted by existing drugs, either currently in trials or approved for use in the clinic.

In analyzing the patients' own genomes, the research team determined 8 percent of the men were born with DNA errors that predisposed them to prostate cancer. This finding provides a strong argument for genetic screening for people with a family history of the disease.

Paul Workman, chief executive and president of the Institute of Cancer Research, London, noted the findings open the door to new ways to combat prostate cancer that has spread to other parts of the body, when it becomes life-threatening.

"Cancer becomes lethal at the stage when it spreads round the body and stops responding to treatment, but until now it has been incredibly difficult to find out exactly what is going on genetically at that critical point,” he said.

"This major new study opens up the black box of metastatic cancer, and has found inside a wealth of genetic information that I believe will change the way we think about and treat advanced disease. The study found that almost 90 percent of metastatic tumors had actionable mutations, which means that these findings could make a real difference to large numbers of patients."

The study was funded, in part, by Stand up to Cancer and the Prostate Cancer Foundation.