A new study using a powerful technique to analyze single cells has identified a biomarker that could be a predictor of an individual’s success to PD-1 immunotherapy treatment for melanoma. The study findings and technology utilized are important to improving outcomes to cancer immunotherapy treatments. Currently, most patients do not respond well to treatments and many experience adverse side effects or eventual relapse. The paper describing the research was published in Nature Medicine.
Mass cytometry, the highly sensitive technique used in the study, allows researchers to see specific markers in an individual’s immune system at certain points in time. "What I use here is a very new and nerdy technology, which is called mass cytometry that allows you with a very high sensitivity to make pictures of your immune system. And this is possible because there's artificial intelligence, machine learning combined with algorithms that can make a very complex system easy to visualize,” explains Carsten Krieg, leader of the study. The technique works by ionizing cells with inductively-coupled plasma and analyzing each cell with a mass spectrometer. AI and bioinformatics are used to create a 2D map that can be used to read the results and biomarker profiles of individual blood cells.
This specific study used mass cytometry to analyze blood samples of stage IV melanoma patients before and after 12 weeks of anti-PD-1 immune checkpoint therapy. The results showed that patients with a higher number of monocytes in their blood before treatment had a better response to the therapy. Identifying predictive biomarkers with this research could assist clinicians in improving patient outcomes by identifying those that who are most likely to respond to certain treatments.
The research team is also interested in using this technique to look more closely and over a longer time period at how cells interact in the tumor microenvironment to obtain more context. "We now have Instagram pictures, a picture before therapy and a picture during therapy. But you can make many more of these pictures, so you're looking after three months, after half a year, a year," he said.