INTERLEUKIN-2 AND INTERLEUKIN-4 DISPLAY POTENT ANTITUMOR-ACTIVITY ON RAT MEDULLARY-THYROID CARCINOMA-CELLS

Currently, surgical resection is the only treatment used for human med ullary thyroid carcinoma (MTC). However, as metastases are commonly ob served, we investigated the potential of adjuvant therapy with interle ukin-2 (IL-2) and interleukin-4 (IL-4) in a rat model. The interleukin s were delivered by means of xenogeneic tumour cells engineered to sec rete IL-2 and IL-4. We found that when a mixture of MTC cells and IL-2 or IL-4 secreting cells were implanted in rats, the growth of the res ulting tumours was inhibited as a function of the number of interleuki n-secreting cells in the inoculum. Moreover, association of the two in terleukins exerted a synergistic antitumour effect. These experimental results, showing thyroid C cell tumour rejection, are of major intere st, as they show the potential therapeutic application for these two i nterleukins, which could be used, in particular, as postsurgical adjuv ants.