Persistent antigen exposure leads to the accumulation of lymphocytes and subsequent tertiary lymphoid structures (TLS). We investigated the relationship of tumor microenvironment (TME) with respect to programmed death ligand 1 (PD-L1), its receptor programmed death 1 (PD-1), and TLS in upper tract urothelial carcinoma (UTUC) cases and compared them with UTUC associated with urothelial bladder carcinoma (UTUC-BCa).
We retrospectively identified 72 patients with UTUC. Representative slides were reviewed, and TLS were counted. Immunohistochemical stains for PD-1 and PD-L1 were performed. PD-1-positive lymphocytes were counted and H-score for PD-L1-positive membranous staining was determined.
PD-L1 expression in the tumor was present in 55.1% of the UTUC cases. Higher stage was associated with increased PD-L1 expression (P = .035). TLS were present in 33.3% and their presence was significantly associated with PD-L1 positivity (P = .024). This association remained significant after adjustment for UTUC-BCa. TLS were also associated with a greater number of infiltrating PD-1-positive lymphocytes (P = .013).
This study is one of the first comparative studies of the TME in UTUC and UTUC-BCa. PD-L1 is expressed in a subset of UTUC and is associated with TLS. The presence of TLS is an inherent characteristic of UTUC and not secondary to the presence of BCa.
American journal of clinical pathology. 2020 Aug 31 [Epub ahead of print]
Maria E Smith, Sahar J Farahani, Timothy Chao, Matthew Palmer, Aileen Arriola, Priti Lal
Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, Philadelphia., Department of Pathology and Laboratory Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA.