Screening for cytogenetic alterations in the PD-L1/PD-L2 locus by FISH and WGS. FISH was performed on 179 samples and WGS on 24 samples. A number of samples underwent both analyses. In total, the status of the PD-L1/PD-L2 locus was made known across 190 DLBCL samples. (A) FISH probes and examples of cytogenetic alterations. The probes targeting the 5′ end of the PD-L1/PD-L2 locus were labeled in red and those targeting the 3′ end in green. A split signal indicative of a translocation is characterized by the lack of colocalization of the green and red probes within a nucleus. Gain is defined as the presence of 3 to 4 target loci within a cell, whereas amplification corresponds to ≥5 copies of the loci within a cell. (B) Distribution of PD-L1/PD-L2 translocations, gains, and amplifications across the different cohorts investigated. Data acquired by FISH and WGS. (C) Distribution of alterations in the PD-L1/PD-L2 locus in the 2 disease subtypes across the different cohorts. Fisher exact test was used for comparison of the frequency of these alterations between GCB and non-GCB samples.