Fig. 1

Genetic and immunohistochemical analyses of PD-L1 ligand expression. (A) Representative images of FISH results for the various categories. PD-L1 in Green (a), and centromeric probe (CEP9) in Red (b). (1) disomy (normal copy numbers); (2) Deletion (target:control probe ratio of < 0.85); (3) Polysomic (target:control probe ratio of 1:1, but more than five copies of the target probe); (4) Amplification (target:control probe ratio of > 2:1 or the target probe > 10). (B, C, D) PD-L1 immunohistochemistry in the colon cancer cases with PD-L1 deletion, disomy, polysomy, and amplification (tumor cells for B, immunocytes for C, tumor cells plus immonocytes for D); (E) PD-1 IHC in the same CRC cases. Scale bar = 50 μm