CXCR4 and lymphoma: Interestingly, we detected that in the infiltrated BM samples, an average of 80% of lymphoma cells expressed CXCR4 and an average of 35% of them expressed CXCL12, whereas in the surrounding tissue (stroma) as well as in the BM samples without involvement, less than 30% of the stroma cells expressed CXCR4 and CXCL12 (Figure 2c I–IV).