Paclitaxel is a chemotherapy drug commonly used to treat breast and ovarian cancer, but some tumours can become resistant over time and start growing again.

A computer program has been trained to grade breast cancer, predicting which tumours are associated with worse outcomes and, therefore, deserve more aggressive treatment.

The SPOT-Light test can measure how many HER2 genes are present in a sample of breast tumor; the more genes there are, the more likely the tumor will respond to treatment with Herceptin.