Figure 6. Expression of cyclooxygenase-2 (COX-2), CD38, and CD20. A-C: Immunohistochemistry of adjacent sections of tissue with anti-CD38, anti-COX-2, and anti-CD20 antibodies (B cell marker) was performed in case 11. CD38-expressing plasma cells were scattered through the stromal area; however, CD20-expressing cells were rare. D, E: CD38-expressing plasma cells were clustered around the blood vessel; however, COX-2-expressing cells showed different distributions from inflammatory cells expressing CD38.