The value of serum levels of IL-6, TNF-alpha, and erythropoietin in metastatic malignant melanoma

In order to study the relation to the metastatic profile and survival, we evaluated the association between pretreatment serum levels of IL-6, TNF-alpha, and erythropoietin (EPO) and metastatic distribution and survival in 16 patients with metastatic malignant melanoma. IL-6 and TNF-alpha immunoassay (R&D Systems, Inc. Minneapolis, USA) employs the quantitative sandwich enzyme immunoassay technique. The Quantikine IVD EPO ELISA (R&D Systems, Inc.) is based on the double-antibody sandwich method. The baseline serum IL-6 and EPO levels were significantly higher in patients with metastatic malignant melanoma than in the control group (p = 0.009 and p = 0.033, respectively). Serum IL-6 levels were higher in patients with weight loss (P = 0.02), who were anemic (p = 0.026), with elevated serum LDH levels (p = 0.028), and who were chemotherapy nonresponding (p = 0.016). The relationship of serum IL-6 concentration to the tumor burden was not determined. Only serum EPO level was influenced by hemoglobin status (p = 0.001). No difference was shown among these three parameters. Elevated serum IL-6 concentration (p = 0.002) was found to be an adverse prognostic factor in patients with poor performance status, weight loss, low serum hemoglobin, elevated serum LDH, and unresponsive to chemotherapy. On the other hand, both serum TNF-alpha and EPO levels were of no prognostic value. Serum levels of IL-6 were found to be prognostic factors as valuable as serum LDH levels in patients with metastatic malignant melanoma. Their prognostic value should be further evaluated in a larger patient population.