CD5 and neoplasm: Through immunohistochemistry, the tumor cells were found to express B-cell markers, including CD20 (Figure 3A) and PAX5, and co-express the germinal center markers CD10, BCL6, and IgM (Figure 3B–D), and they were found to be negative for BCL2 (Figure 3E), Cyclin D1, CD23, CD5, and TdT.