The contribution of CXCR4 silencing to the reduction in proliferation, cell adhesion to bone marrow stroma cells, and colony formation of MCL cells has also been reported by Chen et al. In vivo, the presence of quiescent MCL cells in the bone marrow was also reduced by CXCR4 silencing, whereas the co-culture of MCL cells with human bone marrow stromal cells, or SDF-1, led to markedly increased MCL colony formation [50]. Here, CXCR4 is linked to mantle cell lymphoma.