sTILs and IHC
tumor
TUMOR, PRIMARY TUMORS
FFPE tumor blocks of archived primary tumors and newly collected biopsies of metastatic lesions were used for sTIL assessment and CD8 and PD-L1 (SP142) IHC staining. IHC of FFPE tumor samples was performed on a BenchMark Ultra autostainer (Ventana Medical Systems). Briefly, paraffin sections were cut at 3 μm, heated at 75 °C for 28 min and deparaffinized in the instrument with EZ prep solution (Ventana Medical Systems). Heat-induced antigen retrieval was performed using Cell Conditioning 1 (Ventana Medical Systems) for 32 min at 95 °C (CD8) or 48 min at 95 °C (PD-L1). CD8 was detected using clone C8/144B (1:200 dilution, 32 min at 37 °C; Agilent/DAKO) and PD-L1 using clone SP142 (Ready-to-Use dispenser, 16 min at 37 °C; Roche/Ventana). Bound antibodies were detected using the OptiView DAB detection kit (Ventana Medical Systems). Slides were counterstained with hematoxylin and bluing reagent (Ventana Medical Systems). A PANNORAMIC 1000 scanner from 3DHISTECH was used to scan the slides at a magnification of ×40. Scans of all stainings were uploaded on SlideScore (