CD74 and neoplasm: Only the proteins of CD74 (B cells, monocytes, and dendritic cells) and CD68 (histiocytes) were expressed in both primary tumors, while CD80 (granuloma cells) also was expressed in the original GW-584 specimen, but these and all others, including those most usually associated with B-cell neoplasms, were either not translated in any of the tumor transplants examined, or were below the threshold of staining despite using high concentrations of the detection antibodies, which could be related to denaturation of these proteins in the formalin-fixed, paraffin sections stored for many years.