P2RY8 (purinergic receptor P2Y, G-protein-coupled 8), is best known as supplying the promoter that drives CRLF/TSLPR overexpression, upon deletion of an intervening pseudoautosomal region, in certain cases of B-ALL (56, 57). The gene discussed is P2RY8; the disease is precursor B-cell acute lymphoblastic leukemia.