Serum prohepcidin levels are potential prognostic markers in patients with multiple myeloma

Prohepcidin is the prohormone of hepcidin. Anemia is one of the main clinical features in patients with multiple myeloma (MM) and hepcidin may be associated with iron homeostasis in these patients. However, the clinical significance of prohepcidin is not fully understood. In this retrospective study, we measured serum prohepcidin levels using an immunoassay technique to study its clinical significance in 39 MM patients. Serum prohepcidin levels in patients with MM were weakly correlated with alkaline phosphatase (ALP) levels (r=0.32, P=0.048), calculated by Spearman’s rank correlation, but not with other clinical data, including hemoglobin, serum iron or ferritin. In addition, patients with severe renal insufficiency [creatinine clearance (CCr) <50 ml/min] had significantly higher prohepcidin levels compared with patients with mild or no renal insufficiency (CCr ≥50 ml/min, P=0.047). In contrast, low serum prohepcidin levels less than 110 ng/ml were an independent predictor of poor overall survival [hazard ratio (HR), 5.29; 95% confidence interval (CI), 1.65–17.03] in addition to serum creatinine levels of at least 2 mg/dl (HR, 5.32; CI, 1.10–25.64), serum calcium (HR, 3.53; CI, 1.01–12.33) and ECOG performance status grade 4 (HR, 4.15; CI, 1.32–13.09) in the multivariate analysis using Cox proportional hazards model. In the subset of 31 MM patients with CCr ≥50 ml/min, low serum prohepcidin (HR, 5.65; CI, 1.60–19.95) was an indicator of poor prognosis in multivariate analysis. These results indicate that serum prohepcidin levels may be associated with ALP and renal function but not iron homeostasis, in MM patients. In addition, lower serum prohepcidin levels are potential independent indicators of poor overall survival in MM patients regardless of renal function.