Environment and Breast Cancer: Science Review
AboutCancer studies: Experimental details
Maltoni C, Conti B, Perino G, Di Maio V. Further evidence of benzene carcinogenicity. Results on Wistar rats and Swiss mice treated by ingestion. Ann N Y Acad Sci 1988;534:412-26.
Notes
Increases malignant mammary tumors in female mice. 0, 500 mg/kg, 1/day, 4-5days/wk for78 wks, female mice: 2/40, 19/40 carcinoma.
Increases malignant mammary tumors in female mice. 0, 500 mg/kg, 1/day, 4-5days/wk for78 wks, female mice: 2/40, 19/40 carcinoma.
Route
Route of chemical administration: dermal, inhalation, gavage (delivery directly into the
stomach), in feed, subcutaneous injection (under the skin), or intraperitoneal injection (into the
cavity that contains the abdominal organs).
gavage
Doses
Dosage, frequency, and duration of treatment; the sizes of the groups of animals
involved and what age the animals were at the beginning of the study.
0, 500 mg/kg, 1/day, 4-5days/wk for 104 wks (rats) and 78 wks (mice) . 40 in each dose group. Animals were 7 wks old at start of experiment.
Time after cessation of dosing
How long the animals were observed after the chemical was no
longer being administered and before death of the animals.
kept under observation until spontaneous death
Mammary tumors, malignant
Development of malignant mammary gland tumors follows the
same format as for benign, as described above.
female mice: 2/40, 19/40 carcinoma
Comments
This field contains information on the survival rates of the animals and the body
weight trends in order to evaluate whether these factors were likely to have affected the
generation of mammary gland tumors. Mammary gland tumors tend to develop later in an
animal’s life, so studies with lowered survival could mean that animals died before mammary
gland tumors could develop. Decreased weight (perhaps due to toxicity of the chemical) can
decrease the development of tumors. This field may also contain other comments about the
design or outcome of the study.
Survival in rats treated with benzene was decreased, mice not. Body weight was decreased in all treated animals, especially males.
Other tumors
A list of other tumors that developed in the study that were treatment related.
Zymbal gland, oral, lung, nasal
CPDB TD50 (mg/kg-d)
Data excerpted from the CPDB database that is defined as the "dose-rate in
mg/kg body wt/day which, if administered chronically for the standard lifespan of the species,
will halve the probability of remaining tumorless throughout that period". The CPDB
calculated values for all tumor endpoints listed as well as for total tumors. The range of
mammary gland tumors TD50s is provided, as well as an overall range.
Mammary: 279, Overall: 150-8700