EXPERIMENTAL APPROACHES FOR THE TREATMENT OF MURINE B16 MELANOMAS OF VARIOUS SIZES .1. LOCAL INJECTION OF ETHANOL WITH A COMBINATION OF INTERLEUKIN-2 OR MICROWAVAL HYPERTHERMIA FOR B16 MELANOMAS WITH A SIZE OFLESS-THAN 7 MM IN DIAMETER

The effects of local absolute ethanol injection combined with administ ration of interleukin-2 (IL-2) or microwaval hyperthermia in murine B1 6 melanomas with a size of approximately 7 mm in diameter were investi gated. The groups of melanoma-burdened mice treated with both local et hanol injection and local or intra-abdominal administration of IL-2 sh owed clear suppression of any recurrence of melanoma once the melanoma s had been destroyed by ethanol injection and a concomitant prolongati on of the survival rimes. Also, local injection of ethanol in combinat ion with local microwaval hyperthermia at 43 degrees C for 15 min twic e a week caused complete cures in B16 melanomas with a size of less th an 7 mm in diameter. The infiltrations of T lymphocytes and NK cells w ere augmented in the melanomas treated with ethanol injection and loca l injection of IL-2. However, the melanomas treated with ethanol injec tion and intra-abdominal injection of IL-2 hardly showed any infiltrat ion of such immune cells, although the growth of melanomas was effecti vely suppressed. In the case of treatment with ethanol and hyperthermi a, slight infiltration of NK cells was observed in the melanoma nests as well as in the interstitials. Thus, the direct injection of absolut e ethanol in combination with IL-2 or microwaval hyperthermia is effec tive dr even curative in the treatment of murine B16 melanomas with a size of less than 7 mm in diameter. (C) 1997 Elsevier Science Ireland Ltd.