PTPRC and B-cell neoplasm: Immunostaining for CD45 is typically negative in Reed-Sternberg cells in classic Hodgkin lymphoma, the majority of plasmacytic neoplasms, approximately 10 % of precursor B-cell neoplasms, some anaplastic large cell lymphomas, and rarely other non-Hodgkin lymphomas including DLBCL [8, 9].