Expression of Wnt receptors in hematopoietic cells. Several Wnt receptors have been found to be uniquely expressed in HSC when compared to the terminally-differentiated lineages, including lymphoid cells (NK cells, T cells, and B cells) and myeloid cells (macrophages, granulocytes, and erythrocytes). Among them, both canonical receptors such as Fzd4 (a) and non-canonical receptors such as Ryk (b) are highly expressed in HSC. The average expression value was derived from a normalized microarray (AffyMoe430 2.0 Array) data (n=2).