EPO and melanoma: We first examined the expression of both chains, IL-27Rα and gp130, of IL-27R on a panel of nine tumor cell lines, including 4 AML cell lines (HL-60, KG-1, OCI-AML5, U937), 3 erythroleukemic cell lines (TF-1, UT-7, UT-7/EPO), an acute T-cell leukemic cell line (Jurkat), and a melanoma cell line (A375) at both mRNA and cell surface levels to identify IL-27R-positive tumor cell lines.