Cystatin-C is an independent prognostic factor for survival in multiple myeloma and is reduced by bortezomib administration

Abstract

Background Renal impairment is a common complication of multiple myeloma. Cystatin-C is considered an accurate marker of glomerular filtration rate in several renal disorders. Microarray analysis has revealed that cystatin-C is one of the most highly up-regulated genes in multiple myeloma. The aim of this study was to evaluate the serum levels of cystatin-C in myeloma patients, explore possible correlations with clinical data, including survival, and assess the effect of bortezomib on cystatin-C in relapsed multiple myeloma.Design and Methods We measured serum cystatin-C in 157 newly diagnosed, previously untreated myeloma patients, in 28 patients with relapsed disease pre- and post-bortezomib therapy and in 52 healthy controls, using a latex particle-enhanced nephelometric immunoassay.Results In newly diagnosed patients, cystatin-C was elevated and showed strong correlations with advanced ISS stage, extensive bone disease, high β2-microglobulin, high serum creatinine, and low creatinine clearance. Multivariate analysis revealed that only cystatin-C and lactate dehydrogenase had an independent prognostic impact on patients’ survival. The combination of cystatin-C and lactate dehydrogenase revealed three prognostic groups of patients: a high-risk group (both elevated cystatin-C and lactate dehydrogenase) with a median survival of 24 months, an intermediate-risk group (elevated cystatin-C or elevated lactate dehydrogenase) with a median survival of 48 months and a low-risk group (both low cystatin-C and lactate dehydrogenase) in which median survival has not yet been reached (p