[Molecular predictors in immune oncology]

[Predictive diagnostics for checkpoint inhibitors]

Checkpoint inhibitors have revolutionized oncological treatment in many cancers and added a new immuno-oncological treatment pillar to the medicinal arsenal of conventional and molecularly targeted therapies. In monotherapy and in combination therapies, however, not all patients respond equally well, even in generally responsive tumor entities. Therefore, since the introduction of these therapies, a major focus has been the research on and implementation of predictive markers for patient selection. The first established biomarker, the expression of the target molecule PD-L1, has found its way into routine diagnostics in a large number of unfortunately very divergent diagnostic constellations in multiple entities. In addition, some molecular predictors, including the measurement of microsatellite instability and tumor mutational burden, have also been suggested and in some cases are already implemented into routine diagnostics. Additional molecular parameters have been proposed but most of them have not yet found their way into routine patient care. This review article discusses the current status and recent developments in the field of diagnostic response predictors in the context of an immune checkpoint blockade.