Expression of C-reactive protein by renal cell carcinomas and unaffected surrounding renal tissue.
BACKGROUND
Elevation of plasma C-reactive protein (CRP) is common in patients with renal cell carcinoma (RCC). Renal tubular epithelial cells are capable of synthesizing CRP. Although production of interleukin (IL)-6 has been described in RCC, CRP expression by carcinoma cells has yet not been investigated.


METHODS
In the present study we analyzed CRP plasma levels as well as intratumoral CRP and IL-6 expression of RCC from 40 patients who underwent radical nephrectomy by means of quantitative real-time polymerase chain reaction (PCR) and immunohistochemistry. For each tumor, specimens were obtained from tumor center, tumor margin, and unaffected surrounding renal tissue.


RESULTS
Preoperative plasma CRP levels correlated significantly with tumor stage (P = 0.05) and grade (P < 0.01). CRP mRNA expression was detected in 26 of 33 (79%), 30 of 36 (83%), and 32 of 36 (89%) samples from tumor center, tumor margin, and unaffected surrounding tissue, respectively. However, levels of CRP mRNA were significantly higher in tumor tissue compared to adjacent renal tissue (P < 0.01). Clear cell carcinoma exhibited significantly higher CRP mRNA levels than papillary carcinoma (P < 0.05). CRP plasma levels correlated significantly with quantitative levels of CRP mRNA within tumors (P < 0.0001). Immunohistochemically, strong CRP production was observed both in tumor cells and in tubular epithelial cells in unaffected tissue, respectively. All kidneys expressed IL-6 mRNA in the tumor and/or the unaffected tissue, but levels of intratumoral IL-6 mRNA showed no significant correlation with CRP plasma levels or local CRP transcription.


CONCLUSIONS
In patients with RCC, a tumor-derived origin of some plasma CRP is likely. Activity of the IL-6/CRP network in RCC contributes to the accumulating evidence of the acute-phase reaction as a local inflammatory process.
Jabs
Wolfram J
WJ
Department of Medicine I, Division of Nephrology, University of Luebeck School of Medicine, Germany. jabs@innerel.uni-luebeck.de
Busse
Marleen
M
Krüger
Stefan
S
Jocham
Dieter
D
Steinhoff
Jürgen
J
Doehn
Christian
C
D000210:Acute-Phase Reaction; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002097:C-Reactive Protein / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D002292:Carcinoma, Renal Cell / Q000276:immunology* / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D015850:Interleukin-6 / Q000097:blood / Q000235:genetics / Q000276:immunology; D007680:Kidney Neoplasms / Q000276:immunology* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis
D015850:Interleukin-6; D012333:RNA, Messenger; D002097:C-Reactive Protein