IL6 and neoplasm: The simple logistic regression analysis revealed a significant association between low serum concentrations of IL-6 and a lower risk of presenting an unfavorable tumor histology (p = 0.048); in addition, low levels of IL-12p40 (p = 0.007), IFN-γ (p = 0.006) and MCP-1 (p = 0.029) were found to be associated with a lower risk of presenting NB in disseminated stages of the disease (INSS 3 and 4).