Panel of Candidate Biomarkers for Renal Cell Carcinoma

Abstract

The timely diagnosis and therapeutic monitoring of human renal cell carcinoma (RCC) is limited by the lack of specific biomarkers. To identify candidate RCC biomarkers, we used 2-DE gel electrophoresis with mass spectrometry and 2-DE spot intensity-based ROC analysis to analyze 18 sets of paired normal and RCC tumor tissue including conventional, papillary, and chromophobe subtypes. Validation was performed with RCC patient plasma samples and confirmed by clustergram, shRNA, and immunohistochemistry assays. Cardinal candidates were evaluated by ELISA. The leading candidate biomarker that was upregulated in RCC samples according to the clustergram and validation analysis was nicotinamide N-methyltransferase (NNMT) (13/15, P < 0.0001). Other upregulated candidate biomarkers that were identified by this method include ferritin, hNSE, NM23, secretagogin, and L-plastin. The upregulation of NNMT in RCC was confirmed by immunoblotting and immunohistochemistry. Analysis of fractionated membrane-associated proteins identified CAP-G, mitofillin, tubulin alpha, RBBP7, and HSP27. Of these, RBBP7 and HSP27 were highly expressed in the chromophobe subtype of RCC (3/3) but were absent from conventional RCC (0/3). The triple combination of the NNMT, FTL, and hNSE biomarkers had the highest predictive capacity of 0.993, while NNMT was the single, most powerful candidate diagnostic biomarker for all types of RCC.

Composite Three-Marker Assay for Early Detection of Kidney Cancer

“…However, no such correlation was observed in breast carcinomas (24). In the previous report (9) and the present study of kidney tumors, LCP1 expression in tumors and the level of LCP1 in plasma of patients was correlated with all stages of kidney tumor. As there is increasing evidence for a role of LCP1 in cancer progression, LCP1 is also a promising marker for RCC.…”

“…Although elevated NNMT expression has been reported in several cancers, the actual expression level might differ between cancers. In fact, our previous report showed significant differential expression of NNMT in several normal and cancer tissues including cervical, lung, liver, and ovarian cancer (9): the normalized intensity of NNMT spots in 2-dimensional gel electrophoresis gels of kidney, cervical, lung, liver, and ovarian cancer was 2,976, 211, 298, 385, and 235 units and that of corresponding normal tissue was 162, 30, 93, 537, and 234 units, respectively. The elevation of NNMT in kidney tumor was especially prominent in comparison with several other cancer tissues including liver, which is a source of NNMT.…”

“…However, no clinically relevant screening assay is currently available to detect asymptomatic RCC (8) and there is, therefore, an urgent need for validated markers of RCC. In a previous study, we reported the identification and verification of several markers for early detection of RCC and suggested their potential as promising candidate markers for early detection of RCC (9). Among these markers, Nmethyltransferase (NNMT), L-plastin (LCP1), and nonmetastatic cells 1 protein (NM23A) are explored in the present study.…”

“…Recombinant protein calibrator, antibody preparation, and biotin labeling of detection antibodies was carried out with the procedures as previously described (9). Briefly, recombinant protein was prepared from fulllength cDNA for NNMT (GeneBank accession number: NM_006169), LCP1 (GeneBank accession number: NM_002298.4), and NM23A (GeneBank accession Table 1.…”

Differencial proteome of clear-cell renal cell carcinoma (ccRCC) tissues

“…Previous studies have shown higher expression of HSP27 in ccRCC (27,(29)(30)(31)(32). We observed the same result.…”