Double immunolabeling of CagA expression in tumor cells of gastric “pure” DLBCL and time to CR of patients with HP-dependent gastric DLBCL. (A) Double immunolabeling of CagA and CD20 in an HP-dependent gastric “pure” DLBCL case with immunohistochemically identified CagA expression. Confocal microscopy showing that most CagA-positive cells (green fluorescence) expressed CD20 (red fluorescence). Image of nucleus (DAPI), or a merged image of CagA and CD20 expression. Left bottom inset, The white arrow represents CagA expression (nuclear or cytoplasmic expression), CD20 expression (cytoplasmic expression), nucleus (DAPI), or the merged images of CagA and CD20 expression; the yellow arrow represents no CagA expression, positive CD20 expression (cytoplasmic expression), nucleus (DAPI), or the merged images of CD20 expression alone. (B) The majority of the tumor cells (red fluorescence, CD20) contain cytoplasmic CagA (green fluorescence). The white arrow represents CagA expression, CD20 expression, nucleus (DAPI), or the merged images of CagA and CD20 expression (the confocal image was viewed at ×630). (C) The majority of the tumor cells (red fluorescence, CD20) contain nuclear or cytoplasmic CagA (green fluorescence). The white arrow represents CagA expression, CD20 expression, nucleus (DAPI), or the merged images of CagA and CD20 expression (the confocal image was viewed at ×630). (D) Time to CR was calculated from the completion of antibiotic treatment to the first evidence of CR through Kaplan-Meier analysis (CagA-positive group vs CagA-negative group, 2-sided log-rank test; P = .05).