Scientists have adapted a technique, used by ecologists to study predator-prey interactions, to predict the survival of breast cancer patients by looking at immune cells that “track” cancer cells.
The test could be developed into a computer assisted prediction tool to be used in hospitals, allowing doctors to identify which patients could benefit from more intensive treatment.
The researchers from The Institute of Cancer Research, London, analysed sections of biopsied tumour samples from 1002 breast cancer patients using powerful imaging and statistical software to quantify the spatial interactions of immune cells and cancer cells.
They found that increased numbers of immune cells that appear to follow and track the whereabouts of cancer cells, predicted better survival in all breast cancer types, and was particularly effective for HER2 positive tumours.
The study was published in the journal Breast Cancer Research and funded by the ICR and the Wellcome Trust.
The researchers used tissue samples routinely collected during treatment, and applied a technique widely used by ecologists known as the Morisita-Horn similarity index.
The test was able to quantify the spatial distribution of immune cells in the cancer tissue and researchers compared this information to 10 year patient survival data. The researchers found that patients who had more associations between their immune cells and their cancer cells had better survival rates.
The new technique was better at predicting breast cancer survival rates than simply counting the number of immune cells in the tissue, and better than the existing prognostic PAM50 test.
Dr Yinyin Yuan, Team Leader in Computational Pathology and Integrative Genomics at the ICR, said: “In the same way that animals find clever ways to avoid their predators, cancer cells find ways to escape the immune system. We have borrowed a technique that is widely used by ecologists and applied it to cancer biology to show how tumours and immune cells interact.
“Our study has shown that by quantifying the complex ecosystem between cancer cells and the immune system, we can identify the tumours that are not being held in check by host defences and may require more intensive treatment. The test can be performed on biopsy samples that are routinely collected as part of standard cancer care, so we hope it won’t be long before tests like these are available in hospitals to help doctors decide how best treat individual patients with breast cancer.”