Higher PD-L1 Immunohistochemical Detection Signal in Frozen Compared to Matched Paraffin-Embedded Formalin-Fixed Tissues.

In the tested patient-matched cohort, there was consistently a higher PD-L1 score in FR than FFPE tissues, regardless of the antibody used, demonstrating a significant effect on PD-L1 detection due to the preservation method. These findings should inspire further work to improve the sensitivity of PD-L1 detection and possibly search for more sensitive antibodies in FFPE tissues.