Environment and Breast Cancer: Science Review

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medroxyprogesterone acetate
CAS RN 71-58-9

Cancer studies: Mammary gland tumors
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Originating list
The list(s) or database(s) in which the chemical was identified as showing an increase in mammary gland tumors. CPDB: Carcinogenic Potency Database, IARC: International Agency for Research on Chemicals Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man summaries, NTP TR: National Toxicology Program (NTP) Technical Reports, NTP 11ROC: NTP 11th Report on Carcinogens, CCRIS: Chemical Carcinogenesis Research Information Service.
IARC Monographs, Chemical Carcinogenesis Research Information System
Mammary gland tumor summary
A summary of findings related to mammary gland tumors, most often excerpted from IARC Monographs or the NTP 11th ROC, and, in some cases, supplemented by our evaluation of individual studies and reviews, is available for the priority chemicals and 67 others.
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Only review sources are listed for this chemical because of lower likelihood of exposure.
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International Agency for Research on Cancer, Monographs on the evaluation of carcinogenic risk of chemicals to man.VOL.: Supplement 7 (1987) (p. 289) Progestins. Summary of Data Reported and Evaluation.
When tested by intramuscular injection in dogs and by subcutaneous implantation in mice, it induced adenocarcinomas of the mammary gland in one study in female mice [ref: 6], and produced malignant mammary tumors in dogs [ref: 1]. After four years of intramuscular treatment of dogs with a human contraceptive dose, a dose-related increase in the incidence of mammary nodules was seen; the incidence of mammary-gland nodules at that time was comparable with that seen in dogs given progesterone at 25 times the canine luteal level [ref: 7]. Female dogs treated with medroxyprogesterone acetate for at least one year had a significant increase in the incidence of large and small mammary nodules as compared with control animals in one study [ref: 8], and a dose-related increase in the incidence of large mammary nodules was found in another after intramuscular administration [ref: 9]. 1. IARC Monographs, 21, 417-429, 1979 6. Lanari, C., Molinolo, A.A. & Pasqualini, C.D. (1986) Induction of mammary adenocarcinomas by medroxyprogesterone acetate in BALB/c female mice. Cancer Lett., 33, 215-223 7. Frank, D.W., Kirton, K.T., Murchison, T.E., Quinlan, W.J., Coleman, M.E., Gilbertson, T.J., Feenstra, E.S. & Kimball, F.A. (1979) Mammary tumors and serum hormones in the bitch treated with medroxyprogesterone acetate or progesterone for four years. Fertil. Steril., 31, 340-346 8. van Os, J.L., van Laar, P.H., Oldenkamp, E.P. & Verschoor, J.S.C. (1981) Oestrus control and the incidence of mammary nodules in bitches, a clinical study with two progestogens. Vet. Q., 3, 46-56 9. Concannon, P.W., Spraker, T.R., Casey, H.W. & Hansel, W. (1981) Gross and histopathologic effects of medroxyprogesterone acetate and progesterone on the mammary glands of adult beagle bitches. Fertil. Steril., 36, 373-38
National Toxicology Program 11th Report on Carcinogens, Table 1. Chemicals nominated to the National Toxicology Program for in-depth toxicological evaluation for carcinogenesis testing in fiscal years 1988-2003.
Not nominated for NTP testing in 1998-2003.