title: Erratum.
abstract: The article by Jean L. Marx on "Human trials of new cancer therapy begin" (Research News, 15 May, p. 778) should have noted that the Sloan-Kettering group collaborated with Ronald Breslow of Columbia University on the discovery that the drug hexamethylene bisacetamide induces the differentiation of mouse leukemia cells, and that it is Breslow who is currently trying to redesign the drug to decrease its side effects in human patients without diminishing its effectiveness.