CD5 and Burkitt lymphoma: Most Burkitt lymphomas are immunoreactive for surface immunoglobulin M (IgM), as well as pan-B cell antigens including CD19, CD20, and CD22, and co-express CD10, CD43, and BCL6, but not CD5, CD23, BCL2, or TdT [16, 17] Nuclear staining with c-myc antibody is positive: in all cases of Burkitt lymphoma, a translocation exists between the c-Myc gene and either the IgH gene, as is found in 80% of cases, or either the kappa or lambda light chain gene, found in the other 20% [18].