Researchers have found a way to find out whether immunotherapy will be effective for patients. This will allow doctors to choose the best treatment for everyone.

A team of European researchers collected tumor tissue samples from cancer patients from hospitals in the UK, Spain and France between 2003 and 2017. Scientists then analyzed the interaction of cancer and immune cells and identified the immune checkpoints responsible for the anti-tumor points.

Biologists have studied one of these checkpoints containing two proteins: PD-1 (present in immune cells known as T lymphocytes) and PD-L1 (present in other types of immune cells and on the surface of many types of tumors).

Typically, when PD-1 binds to PD-L1 on the surface of immune cells, an immune response is triggered. But when PD-L1 is expressed on tumor cells, the immune response is blocked and the tumor continues to grow. In immunotherapy, inhibitors interrupt the interaction between PD-L1 in the tumor and PD-1 in the T cell and restore anti-tumor activity.

Scientists have visualized the PD-1 / PD-L1 link in tumor samples. The findings were used to create the iFRET instrument based on Förster energy transfer. It determines the degree of PD-1 / PD-L1 interaction in cancer tissue samples and also predicts how beneficial immunotherapy will be. According to scientists, it worked as a “chemical ruler” measuring cell-to-cell interactions in the range from one to ten nanometers.

The study analyzed only one control point, and more comprehensive analysis will give a better idea of ​​how we can predict the effectiveness of cancer treatments. The study authors believe that iFRET may be used to monitor other intercellular protein interactions. Moreover, it can be useful in the diagnosis of various diseases. Scientists are now developing other ways to find and analyze the links responsible for the immune response that are related to cancer and cancer treatments.

“Today, decisions about whether to continue treating a patient with checkpoint inhibitors are not made on the basis of the functional state of PD-1 and PD-L1, but on whether they are in the biopsies in principle. However, our work has shown that it is much more important to know that these proteins do interact and are likely to influence tumor survival,” concluded Professor Benafshe Larijani, head of the work.

The research results are published in the journal Cancer Research.