Pd l1 antibody clone 22c3

Pathologic tumor assessment and PD-L1 stainings were carried out in cooperation with the Institute of Pathology, MHH, Germany. Selected samples included the worst differentiation and the rim of necrosis for the primary tumor and cava thrombus, if possible. Immunostaining of 3–5 μm formaldehyde-fixed, paraffin-embedded tissue sections was routinely performed on an automated platform (Ventana ULTRA, Ventana Medical Systems, Tucson, AZ, USA) using a PD-L1 antibody (clone 22C3, 1:40, Agilent, Santa Clara, CA, USA) after heat-induced epitope retrieval with CC1 solution (Ventana Medical Systems). Positive controls (tonsil tissue) were included in all staining procedures.
The evaluation of the following scores was carried out by a trained pathologist, Dr. Jan Hinrich Bräsen (JHB). These scores have been comprehensively described in the literature [10 (link), 12 (link)]. $$\text{CPS}=\frac{\text{Number of stained tumor cells}+\text{Number of stained mononuclear inflammatory cells}}{\text{Total number of tumor cells}}\times 100$$ $$\text{IC - score}\left(\text{\%}\right)\text{=}\frac{\text{Stained immune cells}}{\text{Tumor area}}$$ $$\text{TPS}\left(\text{\%}\right)=\frac{\text{Number of stained tumor cells}}{\text{Total number of tumor cells}}$$