PHYSIOPATHOLOGY OF IL-12 IN HUMAN SOLID NEOPLASMS - BLOOD-LEVELS OF IL-12 IN EARLY OR ADVANCED CANCER-PATIENTS, AND THEIR VARIATIONS WITH SURGERY AND IMMUNOTHERAPY

Experimental studies have shown that IL-12 plays an important role in the activation of the anticancer immune defenses. Unfortunately, at pr esent the behavior of IL-12 secretion in human neoplasms remains to be established. In an attempt to draw some preliminary data about IL-12 secretion in human cancer, in the present study we have evaluated seru m levels of IL-12 in a group of non-metastatic and metastatic solid tu mor patients in relation to the survival time, and their changes in su rgically treated cancer patients and in metastatic patients undergoing immunotherapy with IL-2. Mean serum levels of IL-12 were significantl y higher in metastatic patients (n=40) than in those with locally limi ted solid neoplasm (n=16). Moreover, within the metastatic group, the percent of I-year survival was significantly higher in patients with a bnormally elevated blood concentrations of IL-12 than in those with no rmal values. In the group of 10 patients surgically treated for gastro intestinal tract tumors, the surgical operation induced a significant decline in IL-12 mean serum levels. Finally, in a group of 23 metastat ic renal cell cancer patients treated with IL-12 immunotherapy (6 mill ion IU/day S.C. for 6 days/week for 4 weeks), the treatment was associ ated with a significant and progressive increase in IL-12 mean values. Moreover, serum mean levels of IL-12 observed in therapy in patients with response or stable disease were significantly higher than those f ound in progressing patients. This preliminary study seems to suggest that the evidence of high levels of IL-12 may have a favourable progno stic significance in solid tumor patients, either in baseline conditio ns or in response to IL-2 cancer immunotherapy.