RNASE1 and neoplasm: In some studies, RNase A was shown to inhibit tumor growth in mice and rats at doses up to 1000 mg/kg, while in others the absence of both cytotoxic and antitumor effects was observed, and the lack of antitumor effects was explained by the tight binding of RNase A to intracellular ribonuclease inhibitor (RI) [2,8,11,12,15,16,17].