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In Reply:

Centre Léon Bérard, Lyon, France
Institut Gustav Roussy, Villejuif, France

Altundag et al emphasize the role of interleukin-6 (IL-6) as an inducer of acute-phase proteins, particularly C-reactive protein (CRP). This property was recognized shortly after the identification of IL-6 and is due to an IL-6–induced stimulation of the hepatocyte metabolism.^1,2 As a consequence, a number of these subordinate factors are found elevated in patients with advanced malignant tumors that produce an important amount of IL-6, especially renal adenocarcinoma and myeloma.^3,4 As expected, correlations were found between IL-6 levels and the different inflammatory proteins.^2,4 These perturbations have various consequences that can indeed be defined as paraneoplastic syndromes. Two major clinical entities can be observed among metastatic renal cancer patients: a general inflammatory syndrome and Stauffer's syndrome associated with biologic hepatic dysfunctions.

Moreover, a number of these factors were previously found to be correlated with limited survival or progression of the disease in patients. In a previous study performed in 782 patients, we showed that signs of inflammation (elevated CRP > 50 pg/L or augmented sedimentation rate > 100) were independent prognostic factors for survival.⁵

However, if the prognostic value of an elevated sedimentation rate was confirmed in different independent series of patients and by several authors, the value of CRP remains to be proven.

In addition, we checked the levels of CRP in our subgroup of 138 patients.⁶ Available levels were found in 91 patients. The calculated Spearman's correlation coefficient between CRP and IL-6 levels was 0.55, a value that does not usually indicate a major correlation between two variables. This actually demonstrates that there are some differences in the variations of these two factors.

We can therefore conclude that, if it is valid to consider CRP as strongly correlated with poor survival in patients with metastatic renal carcinoma, we lack arguments to describe CRP level as an independent prognostic factor in these patients. As a consequence, the dosage of serum CRP level cannot be a cheaper substitute to the determination of serum IL-6 level.

Authors' Disclosures of Potential Conflicts of Interest

The authors indicated no potential conflicts of interest.

REFERENCES

1. Castell JV, Gomez-Lechon MJ, David M, et al: Recombinant human interleukin-6 (IL6/BSF-2/HSF) regulates the synthesis of acute-phase proteins in human hepatocytes. FEBS Lett 232:347-350, 1988[CrossRef][Medline]

2. Wechsel HW, Feil G, Lahme S, et al: Control of hepatic parameters in renal cell carcinoma (RCC) by interleukin-6 (IL6). Anticancer Res 19:2577-2582, 1999[Medline]

3. Nachbaur DM, Herold M, Maneschg A, et al: Serum levels of interleudin-6 in multiple myeloma and other hematological disorders: Correlation with disease activity and other prognostic parameters. Ann Hematol 62:54-58, 1991[CrossRef][Medline]

4. Ljungberg B, Grankvist K, Rasmuson T: Serum interleukin-6 in relation to acute-phase reactants and survival in patients with renal cell carcinoma. Eur J Cancer 33:1794-1798, 1997

5. Negrier S, Escudier B, Gomez F, et al: Prognostic factors of survival and rapid progression in 782 patients with metastatic renal carcinoma treated by cytokines: A report from the Groupe Français d'Immunothérapie. Ann Oncol 13:1460-1468, 2002[Abstract/Free Full Text]

6. Negrier S, Perol D, Menetrier-Caux C, et al: Interleukin-6, interleukin-10, and vascular endothelial growth factor in metastatic renal cell carcinoma: Prognostic value of interleukin-6—From the Groupe Français d'Immunothérapie. J Clin Oncol 22:2371-2378, 2004[Abstract/Free Full Text]

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This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Alert me to new issues of the journal Save to my personal folders Download to citation manager Rights & Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Negrier, S. Articles by Escudier, B. Search for Related Content PubMed Articles by Negrier, S. Articles by Escudier, B. Social Bookmarking                            What's this?