in long-term experiments multiple ( five ) intravenous injections ( 100 mg/kg each ) of beta-propiolactone given in a 6 week period elicited only two neoplasms ( a chloro-leukemia and a mammary fibroadenoma ) among 37 animals during the following 12-13 months .
C0006141
mammary
C0178421
fibroadenoma