Serum sIL-6r concentration and MMPC IL-6r expression in relation to rs2228145 genotype and MMPC 1q21 status in 626 MM patients. (A) Serum sIL-6r concentrations with respect to rs2228145 status. (B) Serum sIL-6r concentrations with respect to 1q21 status. (C) MMPC IL-6r expression levels with respect to rs2228145 status. (D) MMPC IL-6r expression levels with respect to 1q21 status.