CXCR4 and lymphoma: To investigate CXCR4 expression in Eμ-Myc mice as compared to WT and Eμ-TCL1 mice as a possible reason for no additional effects of CXCR4 hyperactivation on survival in the Eμ-Myc lymphoma model, we first measured CXCR4 surface expression in the different genotypes.