Paradoxically, L-selectin seems to be overexpressed in CLL cells that reside in the LN and BM niches compared to those circulating in the blood stream, and the long-term culture of CLL cells in vitro is accompanied by an increase in L-selectin expression, suggesting a pro-survival role of this protein in the proliferation centers [124]. The gene discussed is SELL; the disease is B-cell chronic lymphocytic leukemia.