Ribonucleases, once dismissed as uninteresting digestive enzymes, have been
shown to have remarkable biological activities. Onconase (R), from the Nor
thern leopard frog, is currently in clinical trials as a cancer chemotherap
eutic. Recent research has revealed some key factors responsible for the cy
totoxicity of ribonucleases, and may lead to a new class of drugs. (C) 2001
Published by Elsevier Science Ltd.