A tumor is as unique as the person who is affected by it. For a long time, it was assumed this would make treatment more difficult since cancer drugs are not able to be one hundred percent effective in targeting the affected cells. In this interview with MEDICA.de, Professor Ugur Sahin explains why it is precisely these individual mutations that make him hopeful for a new type of therapy.
Professor Sahin, how do you produce a personalized vaccine?
Ugur Sahin: All types of cancer originate in genetic variations, meaning mutations. We develop a vaccine that uses mutations as the target for immunotherapy. The particular challenge here is that every patient or rather every tumor carries different mutations. In the case of epithelial cancers such as breast, lung or colon cancer, there are generally anywhere between one hundred to one hundred thousand mutations. When you take a look at mutations of two randomly chosen patients, the overlap is less than five percent. There are therefore individual mutations in 95 percent of cases. This is why these types of mutations were long being ignored as therapeutic targets. Although there are drugs that are aimed at specific mutations, they only target the overlap percentage. That is why we deliberated how these individual mutations could be utilized in therapy.
Sahin: The therapeutic approach you developed consists of three steps. What are they?
Sahin: During the first step, the tumor is genetically analyzed via next-generation sequencing to determine all of the mutations. Here the tumor’s genetic makeup is compared to that of normal tissue, for instance, blood cells. This analysis lets you generate a list that includes all mutations. The second question is which mutations are suited for immunotherapy. We discovered that 20 percent of these mutations induce immune responses. Of course, this conversely means that 80 percent are not identified by the immune system. We also found out what types of immune responses are triggered by the mutations. Now we are able to predict the immune responses using computer algorithms. We have used a vaccine platform we have been developing over the past 15 years here in Mainz to produce mutation-specific, completely personalized vaccines within a few days.