Patients were determined to have MCPyV-positive tumors if they produced small T-antigen-specific serum antibodies21 (link) or manifested large T-antigen expression in tumor biopsies via immunohistochemistry.22 (link) PD-L1 staining (anti-PD-L1 clone 22C3, Merck & Co, Kenilworth, New Jersey, USA) was performed at QualTek Molecular Laboratories on pretreatment tumor specimens as previously described.17 (link) Specimens were considered PD-L1 positive if ≥1% of tumor cells expressed PD-L1 at the cell surface.16 20 (link)
Neutrophil-to-lymphocyte ratio (NLR) was calculated using absolute neutrophil counts and absolute lymphocyte counts (ALC), determined from automated complete blood counts in peripheral blood specimens obtained at study visits. NLR was calculated at baseline (before initial pembrolizumab infusion) and after each of the first four treatment cycles.
Neutrophil-to-lymphocyte ratio (NLR) was calculated using absolute neutrophil counts and absolute lymphocyte counts (ALC), determined from automated complete blood counts in peripheral blood specimens obtained at study visits. NLR was calculated at baseline (before initial pembrolizumab infusion) and after each of the first four treatment cycles.
