INTERLEUKIN-2 IN NEOADJUVANT THERAPY POTENTIATES INHIBITORY ACTIVITY OF 5-FLUOROURACIL AND INTERFERON IN EXPERIMENTAL LIVER METASTASES

Our previous studies showed that interferon (IFN) used in combination with 5-fluorouracil (5-FU) was effective in inhibiting colorectal tumo r cell metastases to the liver in nude mice. Furthermore, IFN was also effective in neoadjuvant therapy and allowed the combination treatmen t (5-FU+IFN) to be delayed for 2-3 weeks following i.s. injections of tumor cells. In this study, we have examined the potential of interleu kin-2 (IL-2) to substitute for IFN in neoadjuvant therapy. IL-2 was fo und to be equally effective, if not superior, to IFN as a neoadjuvant in inhibiting river and lung metastases with 5-FU+IFN. Moreover, the e ffect of IL-2 was demonstrable even after 1 week, whereas IFN did not have an effect until 2 weeks of neoadjuvant dosing. These studies demo nstrate IL-2 to be more effective than IFN as an immunomodulatory agen t in combination with 5-FU+IFN for the inhibition of liver metastases in nude mice.