ENDOGENOUS INTERLEUKIN-6 LEVELS IN PATIENTS WITH METASTATIC MALIGNANT-MELANOMA - CORRELATION WITH TUMOR BURDEN

The involvement of interleukin (IL-) 6 in malignant disease has been i nvestigated in a variety of different malignancies, To evaluate whethe r serum IL-6 is a useful disease marker in metastatic malignant melano ma (MMM), we studied the time course of endogenous IL-6 secretion in 4 1 patients treated with cisplatinum, IL-2, and IFN-alpha. Furthermore, the relationship of endogenous IL-6 concentrations to the tumor burde n and/or the clinical response was also evaluated, The baseline serum IL-6 levels were significantly higher in patients with MMM than in the control group (P = 0.002), When tumor burden was taken into considera tion, we found that IL-6 levels were higher in patients with high tumo r burden than in patients with low tumor burden, During treatment in t he whole patient population, a higher serum IL-6 level was observed in nonresponding as compared to responding patients at days 7 (P = 0.000 5), 21 (P = 0.002), and 35 (P = 0.009), The follow-up of serum IL-6 in patients with MMM according to the tumor burden and clinical response demonstrated that: (a) IL-6 levels were significantly higher at days 7 and 21 in patients with high tumor burden as compared to those with low tumor burden; and (b) IL-6 levels remain significantly higher in n onresponding patients as compared to responding patients regardless of the tumor burden, From these results, we can conclude that endogenous IL-6 may play a role in the failure of IL-2 therapy in such patients, since the very early IL-6 increase is correlated with the tumor mass and nonresponse to biochemotherapy, Therefore, it seems that the early detection of endogenous IL-6 may represent valuable information for m onitoring the response to biochemotherapy in patients with MMM.