IL6 and neoplasm: ROC analysis was performed for each serum cytokine to assess the correlation between the patients‘ longer survival and tumour response and showed that PGE2 and IL-6 were significant predictors of longer survival (p = 0.033 and 0.031, respectively), while IL-2 and IL-6 predicted tumour response (p = 0.030 and 0.013, respectively).