IL6 and metastatic malignant neoplasm in the lymph nodes: ROC curve analysis showed that the addition of preoperative plasma levels of IL6 and IL6sR to a reference model comprising age, sex and clinical tumor stage significantly improved the discriminating ability for prediction of lymph node metastasis (5%, p < 0.001), ≥ pT3 disease (4%, p < 0.001) and any NOCD (4%, p < 0.001, Table 2).