Serum-soluble IL-2 receptor and IL-6 levels in patients with melanoma.

Elevated soluble IL-2 receptor (sIL-2R) and IL-6 serum concentrations have been reported as adverse prognostic factors in several types of cancer. In order to determine whether these factors are predictive of metastatic progression in melanoma, sIL-2R and IL-6 levels were measured in sera from 172 patients with melanoma and 60 in healthy controls. Mean sIL-2R values were significantly higher in the patients than in normal controls and the highest values were observed in those that developed metastasis during follow-up. However, no correlation was found with the stage of the disease. Serum IL-6 levels were found to be correlated with age and sex, but not correlated with sIL-2R levels. Statistical analysis was based on logistic and Cox regression models. The factors considered were age, sex, stage, disease-free interval and serum sIL-2R and IL-6 levels. The analysis showed that only the sIL-2R value is significantly linked to metastatic progression. This finding suggests that high serum levels of sIL-2R could be a predictive factor of metastatic progression in malignant melanoma.