Hemizygous deletion of PRDM1 in DLBCLs. Haploid copy number for PRDM1 exons 3, 4, 5, and 7 in tumor nos. 1 through 8 and OCI-Ly3 are shown. OCI-Ly3 was used as a control for hemizygous deletion of PRDM1. Calculations were performed as described in “Materials and methods.” The cut-off limit is indicated by a horizontal line. The value was considered a hemizygous deletion if the haploid copy number was lower than the cut-off. A value higher than the cut-off level supports a normal copy number status.