A gene test that predicts which cancer drugs will be most effective for different people is to be trialled in the US.
The trial will include patients with breast cancer
Preliminary results suggest the test, which looks at the unique molecular traits of a tumour, predicts the best drug with 80% accuracy.
The first clinical trial is planned in 120 breast cancer patients next year.
If the results are good, the test could be applied to all chemotherapy-treated cancers, Nature Medicine reports.
The researchers at Duke University, North Carolina, say the test has the potential to revolutionise cancer care by identifying the right drug for each individual patient.
Lead researcher Dr Anil Potti said the test could save lives and reduce patients' exposure to the toxic side effects of chemotherapy drugs.
He explained: "Chemotherapy will likely continue to be the backbone of many anti-cancer strategies.
"With the new test, we think that physicians will be able to personalise chemotherapy in a way that should improve outcomes."
The trial will compare how well patients respond to chemotherapy selected by the gene test versus chemotherapy chosen by doctors in the usual way.
The test works by scanning thousands of genes from a patient's tumour to produce a "genomic" profile of the cancer's molecular makeup.
The test gives a "genomic" profile of the cancer's molecular makeup
Using the test on cancer cells in the lab, the scientists were able to match the right chemotherapy for the patient's type of the tumour.
When they checked these selections by observing how the patients responded to the drugs in real life, the scientists discovered the predictions were correct more than eight times out of 10.
Josephine Querido of Cancer Research UK said: "Being able to predict who will respond to a chemotherapy drug and who will not is a hot topic for cancer researchers worldwide - it would allow doctors to identify which patients will benefit most from the treatment.
"The results presented in this study are very encouraging, and we hope approaches like these will soon be available in the clinic so that more patients will receive treatments that are right for them."