Cryosurgical Treatment of Primary SV 40 Viral and Adenovirus 7 Transplant Tumors in Hamsters ∗

Abstract

Summary

Studies of cryogenic destruction of virus-induced SV₄₀ tumor and of adenovirus 7 transplant tumor were carried out in hamsters. The effect on the treated tumors as well as on other tumors which were present at the time of cryosurgery or which developed subsequently was noted. The effect on the treated SV₄₀ virus-induced tumor was, at best, temporary and palliative and there was no apparent suppression of untreated tumor. The same general effect was noted with adenovirus 7 transplant tumor except that complete regression of treated tumor occurred in 2 animals and similar regression of an untreated tumor was observed in 1 animal. In the overall, immunodestructive effect subsequent to cryosurgery was weak if present at all. This was consistent with the prior demonstration of destruction of tumor-immunizing quality of tumor antigens by the freeze-thaw procedure and with the commonly observed development of immunologic tolerance in cancer.