Tumor biopsy samples. (A) Representative photomicrographs of HL tumor biopsy samples from different histologic subtypes ([i-iii] MC, NS, and NLP, respectively). The EBV status of tumor tissues was confirmed by EBER in situ hybridization (iv-vi) and LMP1 immunohistochemistry (viii-x). Tissue samples shown in panels iv, v, viii, and ix were positive, while vi and x were negative for EBV. (xii-xiv) LAG-3 protein on tumor-infiltrating lymphocytes in HL biopsies. The numbers of LAG-3⁺ cells in each tissue section were graded as described in Table 2. The tissue sections were graded +++ (xii), ++ (xiv), and negative (xiii). The relevant isotype controls are shown in panels vii, xi, and xv. (i-iii) Original magnification, × 10; (iv-xv) original magnification, × 40. (B) Representative lymph node sections from a patient with lymphocyte-rich EBV-positive classic HL. (i-ii) LAG-3 and FOXP3 protein on tumor-infiltrating lymphocytes, respectively; (iii) dual staining illustrates that the nuclear FOXP3 protein (red) and surface/cytoplasmic LAG-3 protein (brown) do not generally colocalize within the same lymphocyte. Photomicrographs were taken using a Nikon Coolpix 5700 camera (Nikon, Tokyo, Japan) and were acquired with Microsoft Office XP Photo Editor (Microsoft, Seattle, WA). Images were originally magnified under an Olympus CX41 microscope equipped with a 10×/0.65 NA (i-iii) or a 40×/0.25 NA (iv-xv) objective lens (Olympus, Tokyo, Japan).