Immunohistochemical localization of nephrocalcin, a kidney-specific glycoprotein, to renal cell carcinoma

Calcium Oxalate Deposition in Renal Cell Carcinoma Associated With Acquired Cystic Kidney Disease

The main complication of acquired cystic kidney disease (ACKD) is frequent development of renal tumors, including renal cell carcinoma (RCC). Intratumoral deposition of calcium oxalate (CaOx) is a distinct feature of ACKD-associated RCCs, but several features of this type of RCC are not known. Features of the 30 end-stage renal disease (ESRD)-associated RCCs identified within a 13-year period, including eight with CaOx deposition, were analyzed. Pathologic and clinical features of CaOx positive (+) and negative (-) RCCs were evaluated and compared. The CaOx+ RCCs showed higher tendency for bilaterality and multifocality. Seven tumors displayed distinctive morphologic features characterized by tumor cells with ill-defined cell membrane, abundant granular eosinophilic cytoplasm, large nuclei, and prominent nucleoli. One tumor was of clear cell type. Regardless of histologic type, all tumors displayed a proximal tubular differentiation. No significant difference was noted for tumors' stage, proliferation, and apoptosis rate between the CaOx+ and CaOx- RCCs. CaOx+ RCCs account for a significant portion of all ESRD-associated RCCs. The majority of these RCCs display a distinctive morphologic profile. Proximal tubular cell differentiation in conjunction with ESRD-mediated high serum level may be pathogenetically important for intratumoral CaOx deposition. These RCCs seems to have a relatively good prognosis.

Renal cell carcinoma with intratumoral calcium oxalate crystal deposition in patients with acquired cystic disease of the kidney

We describe 2 cases of renal cell carcinoma arising in acquired cystic disease of the kidney (ACDK) in patients with end-stage renal disease undergoing hemodialysis for more than 5 years and provide a brief review of the complications of ACDK. In both cases, abundant calcium oxalate crystals were observed within the tumors. Histologically, one of the tumors was a conventional (clear cell) renal cell carcinoma. The other tumor was a bilateral papillary renal cell carcinoma. Both tumors were high-grade carcinomas with extensive oncocytic (acidophilic) features. Also noted within the kidneys were cysts with atypical papillary hyperplasia. The clinicopathologic findings along with review of the literature suggest a relationship between tumor growth and calcium oxalate crystal deposition in patients undergoing hemodialysis with ACDK.

Mannan-binding lectin (MBL)-associated plasma protein present in human urine inhibits calcium oxalate crystal growth

Mannan-binding lectin (MBL)-associated plasma protein (MAp19) is an alternatively spliced form of MBL-associated serine protease-2, a component of a complement activation cascade. We observed that MAp19 is excreted in human urine. Interestingly, the amount of MAp19 was higher in urine of renal cell carcinoma patients than healthy people. Pretreatment of urine dialysate with 50 mM EDTA increased the recovery of MAp19, suggesting that MAp19 is a calcium-binding protein. The recombinant MAp19 showed a strong inhibition of calcium oxalate crystal growth in vitro in a concentration-dependent manner. Thus, we conclude that MAp19 plays a role in the inhibition of calcium oxalate renal stone formation.