Hindawi Publishing Corporation Bone Marrow Research Volume 2011, Article ID 493697, 9 pages doi:10.1155/2011/493697 Review Article Recent Advances in the Pathogenesis and Management of Cast Nephropathy (Myeloma Kidney) Stephanie Stringer,1, 2, 3 Kolitha Basnayake,1, 2, 3 Colin Hutchison,1, 2, 3 and Paul Cockwell1, 2 1 Renal Institute of Birmingham, University Hospital Birmingham, Birmingham B15 2TH, UK 2 Department of Nephrology, University Hospital Birmingham, Birmingham B15 2TH, UK 3 School of Immunity and Infection, University of Birmingham, Birmingham, B15 2TT, UK Correspondence should be addressed to Stephanie Stringer, stephanie.stringer@uhb.nhs.uk Received 18 November 2010; Accepted 2 March 2011 Academic Editor: Guido Kobbe Copyright © 2011 Stephanie Stringer et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Multiple myeloma is an incurable plasma cell malignancy that is often accompanied by renal failure; there are a number of potential causes of this, of which cast nephropathy is the most important. Renal failure is highly signiﬁcant in myeloma, as patient survival can be stratiﬁed by the severity of the renal impairment. Consequently, there is an ongoing focus on the pathological basis of cast nephropathy and the optimal treatment regimens in this setting, including eﬀective chemotherapy regimens to reduce light chain production and emerging extracorporeal techniques to remove circulating light chains. This paper bridges recent advances in the pathogenesis and management of cast nephropathy in multiple myeloma. 1. Introduction The kidneys are a common target for injury in a large number of acute and chronic diseases that initially develop at nonrenal sites. Where renal injury develops as a secondary consequence of nonrenal disease, then (i) the factors that cause this injury are often complex; (ii) the involvement of the kidneys and the development of subsequent acute kidney injury (AKI) or chronic kidney disease (CKD) has a delete- rious eﬀect on subsequent clinical outcomes. The eﬀective management of kidney disease is an important factor in improving the long-term outcomes of the aﬀected individ- ual. Multiple myeloma (MM) is commonly complicated by kidney injury with a major impact on long-term outcomes; therefore understanding the nature of the kidney damage and the treatment options that are available are crucial for improving outcomes for people with MM and kidney injury. In this paper we will overview the current status of basic and clinical science in this area and show how increasing knowl- edge in both these areas is leading to improvements in clinical outcomes. 2. Multiple Myeloma and the Kidneys Multiple myeloma (MM) is a haematological malignancy characterised by clonal proliferation of plasma cells and associated with end-organ damage. There is production of a monoclonal immunoglobulin (Ig) in over 80% of those aﬀected; each intact monoclonal Ig will include either a kappa light chain (LC) isotype or a lambda LC isotype; in the large majority of cases of intact monoclonal Ig in MM there is excess production of the relevant monoclonal LC, and in around 20% of cases there is LC monoclonality with no detectable intact immunoglobulin [1]. This detectable Ig LC is often referred to as free light chain (FLC). The incidence of new-onset (ﬁrst diagnosis) MM in the United Kingdom is around 6.5 per 100,000 in Caucasians, 10-9-18.2/100,000 in Blacks, and 3.6–6.4/100,000 in Asians [2]. At presentation at least 50% of patients will have AKI of a variable degree, and around 10% have severe AKI from which they will die within weeks unless they are treated with renal replacement therapy by dialysis [3]. The prognosis for patients with MM and AKI is worse than that for those with