Beta-Propiolactone Is a Carcinogen

To the Editor:— The article by Allen and Murphy inThe Journal, April 16, page 1759, on the use of beta-propiolactone for the sterilization of instruments and materials omits a very important consideration in the use of this substance. Beta-propiolactone is a carcinogen. Local sarcomas have been produced by subcutaneous injection of beta-propiolactone in rats (Walpole and others:Brit. J. Pharmacol.9:306 [Sept.] 1954), and squamous papillomas and squamous carcinomas have been produced in mice by painting the skin with this material (Roe and Glendenning:Brit. J. Cancer10:357 [June] 1956). In the laboratory of Dr. Paul Kotin we have produced sarcomas and squamous papillomas in mice by a single subcutaneous injection of a minute amount (.002 ml.) of beta-propiolactone (recent unpublished data). This information is brought to the attention of the readers ofThe Journalso that it may be more widely disseminated.