What are the advantages of the blood test compared to taking a tissue sample?
Zoche: In general, the analysis of a tissue sample is still the gold standard for tumor diagnostics. It allows histological findings to be obtained that are not possible with a blood test. However, tumor DNA from liquid biopsy has the advantage of identifying mutations from different metastases simultaneously. Tissue biopsy typically involves puncturing only one metastasis, which is then used to determine the tumor profile. However, different metastases may have different tumor profiles.
Another advantage is that for those patients for whom we can no longer perform a tissue biopsy at all for health reasons, the blood test offers a very good alternative for tumor profiling. Only a few milliliters of blood are needed for a liquid biopsy. However, we cannot analyze certain changes in DNA, genomic amplifications and fusions, as well from blood as we can from a tissue biopsy.
Where do you still see potential to develop molecular pathology further?
Zoche: Comprehensive molecular tumor profiling is still not performed on all cancer patients. However, this should be part of standard diagnostics today. Low-cost tests also still need to be established in the area of tumor monitoring. Here we are working with diagnostics companies to make such tests available soon to those affected. In the early detection of cancer, there are already approaches, for example by companies in the USA, that test the blood of healthy people for possible tumor DNA. However, a great deal of development work is still needed here, as predicting whether someone has cancer or not is still far from accurate enough. The goal in tumor profiling is to sequence as comprehensively as possible in order to be able to examine the complete tumor genome of those affected. Only in this way can the medical staff treating the cancer discuss and implement all possible personalized therapy options with the affected person.