PPIB and diffuse large B-cell lymphoma: The characteristic red punctuate nuclear staining pattern of such assay was observed, usually as a single dot and occasionally during mitotic division, in scattered rare cells of morphologically clear tumor origin in most EBER-negative/EBNA1-qPCR-positive lymphoma cases tested (6/9 BL, 8/10 DLBCL, 7/10 cHL, 2/3 FL), but in no tumor cells of any EBER- negative/EBNA1-qPCR-negative cases (2 BL, 5 DLBCL, 8 cHL, 5 FL) (Fig. 2; Supplementary Table 1) that were instead positive for the control PPIB mRNA probe (not shown).