Programmed death-ligand 1 expression in human papillomavirus-independent cervical adenocarcinoma and its prognostic significance

Aims: In the 2020 World Health Organization classification of female genital tumours, endocervical adenocarcinomas (ECAs) are subclassified into human papillomavirus (HPV)-associated (HPVA) and HPV-independent (HPVI) groups on the basis of their distinct aetiologies and clinical behaviours. The aim of this study was to investigate programmed death-ligand 1 (PD-L1) expression and its prognostic value in HPVI ECA and HPVA ECA, and compare these between the two entities. Methods and results: A total of 93 ECAs accessioned between 2013 and 2020 were selected for further analysis, including 48 usual-type HPVA ECAs and 45 HPVI ECAs. Then, we evaluated PD-L1 expression in whole tissue sections of these cases by using the tumour proportion score (TPS) and the combined positive score (CPS). Heterogeneous PD-L1 expression was observed in both HPVI ECAs and usual-type HPVA ECAs. However, no significant difference in PD-L1 expression was seen among different histological types of ECA when either the CPS or the TPS was used. Gastric-type ECA (GEA) was associated with higher clinical stage (P = 0.001), worse progression-free survival (PFS) (P = 0.008) and worse overall survival (OS) (P = 0.02) than usual-type HPVA ECA and non-GEA HPVI ECA. When the TPS was used, PD-L1-positive GEA was associated with significantly worse PFS (P = 0.03) and OS (P = 0.015) than PD-L1-negative GEA. Conclusions: Our data show frequent PD-L1 expression in HPVI ECAs, supporting the potential role of the programmed cell death protein 1/PD-L1 pathway as a therapeutic target for these tumours. Our data also support PD-L1 as a negative prognostic marker associated with a potentially unfavourable outcome for GEAs.