CXCR4 immunohistochemistry (IHC) has been shown to be highly positive e.g. in mucosa-associated lymphoid tissue (MALT) type lymphomas (15) and CXCR4 antagonists such as plerixafor prevent disease progression in non-Hodgkin lymphoma in vitro especially when combined with rituximab (16–18). This evidence concerns the gene CXCR4 and lymphoma.