The role of cystatin C in multiple myeloma.

Abstract

Renal insufficiency is one of the common complications in multiple myeloma (MM) and an independent factor indicating a poor prognosis. Cystatin C (Cys C) is considered to be expected to replace creatinine to calculate glomerular filtration rate due to its own characteristics. Gene expression analysis suggested that cystatin C is up-regulated nearly 50-fold in patients with multiple myeloma. To further clarify the role of cystatin C in multiple myeloma, we retrospectively evaluated pretreatment cystatin C levels in 195 newly diagnosed patients through statistical analysis. The elevation of serum cystatin C was positively related to the elevation of serum creatinine (P<.001), LDH (P=.006), β2-microglobulin (P<.001), bone marrow plasma cell proportion (P=.005) and the reduction of hemoglobin levels (P<.001). Patients with serum cystatin C levels >1.6mg/L had a significantly shorter progression-free survival (PFS) or overall survival (OS) than patients with serum cystatin C levels <1.6mg/L (median PFS: median unreached vs 16.7months, P<.001; median OS: 68months vs 42months, P=.014). Although serum cystatin C is not an independent prognostic factor of OS and PFS in patients with multiple myeloma, serum cystatin C can be considered as a sensitive indicator to differentiate well OS and PFS in the group of ISS II patients. Serum cystatin C is associated with tumor burden of multiple myeloma and cystatin C can further differentiate the prognosis of ISS II patients. More prospective studies are required to explore the role of serum cystatin C in multiple myeloma.