Gene-screening has been used to identify women most likely to benefit from one type of breast cancer chemotherapy.
The technique could lead to a simple test enabling doctors to administer personalised treatment, say researchers. In future the same method may offer a way of predicting which patients will respond to other cancer drugs.
The international team of scientists scanned 829 genes in breast cancer tumour cells.
They selected out six which if missing or faulty would prevent the chemotherapy agent paclitaxel working properly.
A patient study then showed how the genes could reveal in advance which women were likely to respond best to the drug.
Lead researcher Dr Charles Swanton, from the Cancer Research UK charity's London Research Institute, said: “A great challenge is determining which patients will benefit from particular cancer drugs. It is hoped that this research is a step towards more rapid developments in this type of personalised medicine.”