cis-Dichlorodiammineplatinum (cis-DDP), an anticancer agent sometimes used in pregnant women for the treatment of malignant ovarian and uterine tumors, was tested for transplacental carcinogenic and/or tumor-initiating effects in SENCAR mice. Pregnant mice were given a single i.p. injection of either cis-DDP (7.5 mg/kg body weight) in 2.5% NaCl or the same weight-adjusted volume of NaCl (5 ml/kg body weight) on day 17 of gestation. Offspring were delivered and raised by their natural mothers until weaning at 3 weeks of age. Starting at week 4, offspring in experimental groups received topical applications of 2 µg 12-O-tetradecanoylphorbol-13-acetate (TPA) in acetone twice a week for 20 weeks while those in control groups received only acetone (0.2 ml/application) for the same duration. The experiment was terminated at 25 weeks of age. A high incidence (18 of 37; 48.7%) of papillomas was observed in offspring exposed transplacentally to cis-DDP and postnatally to TPA, while only 10% (4 of 40) of offspring exposed to TPA alone developed such tumors (P < 0.0002). Although no skin tumors were observed without TPA promotion, transplacental administration of cis-DDP resulted in development of thymic lymphomas, lung tumors, and proliferative kidney lesions in offspring. These results provide the first evidence that cis-DDP can initiate and/or induce preneoplastic and neoplastic lesions in multiple tissues transplacentally.
These results were presented in part at the 84th Annual Meeting of the American Association for Cancer Research held in Orlando, FL, on May 19–23, 1993.