Keith Kerr, BSc, MB, ChB, FRCPath, FRCPE, of the University of Aberdeen, Aberdeen, Scotland, discusses PD-L1 immunohistochemistry in lung cancer.
Right now the only biomarker with validated data in lung cancer is PD-L1 immunohistochemistry. It is perceived as not being a good biomarker, but it is unfairly judged says Kerr.
It often gets compared to EGFR mutation or ALK translocation which are very effective biomarkers, but PD-L1 is not the only controlling factor within the immune response and it will never have the level of predictive power as those biomarkers. Expectations of PD-L1 need to be downgraded, says Kerr.
However, it can be improved. Right now each PD-L1 inhibitor has its own immunohistochemistry test and they are not all the same. It is not practical to do multiple test, so there needs to be simplification, says Keer.