Immunohistochemistry for E2A and ID2 from LBLs and thymus of premature infants. Note the nuclear E2A stain in both the thymus (A) and a T-LBL (B). For ID2, the staining is nuclear in the normal thymus (C) but cytoplasmic in a case of T-LBL (D). (A-D, × 400, immunohistochemistry using formalin-fixed, paraffin-embedded tissue sections and hematoxylin counterstain). Images were visualized under an Olympus BX60 microscope equipped with a Plan-Apo 40×/0.95 objective lens, and were captured with a DP70 digital camera (Olympus, Tokyo, Japan).