Controversy regarding the prognostic and/or predictive role of PD-1 and PD-L1 expression for upper tract urothelial carcinoma (UTUC) could partly be explained by inconsistencies in the immunohistochemistry (IHC) methodology. Objective is to standardize the methodology for routine evaluation of PD-1 and PD-L1 expression in UTUC patients.
Twenty-two cases treated with radical nephroureterectomy between 1996 and 2015 at 11 French hospitals were randomly selected to compare different methodologies for evaluation of PD-1 and PD-L1 expression. IHC was carried out on whole tissue sections and 0.6 mm- or 2 mm-core tissue micro-arrays (TMAs) using PD-1 NAT105 and PD-L1 28.8 or E1L3N on both tumor cells and tumor-infiltrating immune cells (TILs). Results obtained with whole tissue sections (WTS) were compared to those obtained with 0.6 mm- and 2 mm-core TMAs. Concordance was evaluated using Kappa coefficient.
For evaluation of PD-1 and PD-L1 expression, the best concordance with WTS was observed using the PD-1 NAT105 and PD-L1 28.8 antibody on 2 mm-core TMAs, with 5% cut off for positivity on TILs and tumor cells, respectively (Kappa = 0.8).
The most accurate methodology for routine evaluation of PD-1 and PD-L1 expression in UTUC may be based on 2 mm-core TMAs using NAT105 and 28.8 antibodies with a 5% cut off for positivity on TILs and tumor cells, respectively.
The Canadian journal of urology. 2021 Jun [Epub]
Luca Campedel, Thomas Seisen, Justine Varinot, Géraldine Cancel-Tassin, Alain Ruffion, Emilien Seizilles De Mazancourt, Myriam Decaussin-Petrucci, Grégoire Robert, Nam-Son Vuong, Magali Philipp, Eva Compérat, Morgan Rouprêt, Olivier Cussenot
Sorbonne Université, GRC n∘5, Predictive Onco-Urology, AP-HP, Hôpital de la Pitié Salpêtrière, Paris, France.