CT antigen immunohistochemistry in stage-III multiple myeloma. (A-E) Patient no. 1. (A) CT7-33 mAb (anti-CT7), greater than 75% of plasma cells positive (graded ++++), × 20 original magnification. (B) Negative control staining without primary antibody. (C) Detail showing predominantly cytoplasmic distribution of staining, × 40 original magnification. (D) M3H67 mAb (anti–MAGE-A3/6), approximately 50% of malignant cells positive (++), × 20 original magnification. (E) Detail showing cytoplasmic and nuclear distribution of staining, × 40 original magnification. (F-J) Patient no. 2. (F) CT7-33 mAb, approximately 20% of plasma cells positive (+), × 20 original magnification. (G) Negative control staining without primary antibody. (H) Detail showing predominantly cytoplasmic distribution of staining, × 40 original magnification. (I) M3H67 mAb, less than 5% of malignant cells positive (focal), × 20 original magnification. (J) Detail showing cytoplasmic and nuclear distribution of staining, × 40 original magnification.