Environment and Breast Cancer: Science Review
AboutCancer studies: Experimental details
National Toxicology Program Technical Report 267
Notes
Nonsignificant increase in malignant mammary tumors in mice. female mice:0, 200, 400 ppm for 6 hrs/d, 5 d/wk for 103 wks. 0/50, 3/50, 3/50 adenocarcinoma. IARC dosen't note mammary tumors from this study.
Nonsignificant increase in malignant mammary tumors in mice. female mice:0, 200, 400 ppm for 6 hrs/d, 5 d/wk for 103 wks. 0/50, 3/50, 3/50 adenocarcinoma. IARC dosen't note mammary tumors from this study.
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).
inhalation
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, 200, 400 ppm for 6 hrs/d, 5 d/wk for 103 wks. 50 animals of each sex per dose group. Animals were 7-9 wks old at beginning of study.
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.
none
Mammary tumors, malignant
Development of malignant mammary gland tumors follows the
same format as for benign, as described above.
female mice: 0/50, 3/50, 3/50 adenocarcinoma
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.
There were no mortality problems in rats. The high and low dose mice groups of both sexes had diminished survival. All high dose groups of both sexes and both animals had lower weight.
Other tumors
A list of other tumors that developed in the study that were treatment related.
nasal, thyroid
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: 2770, overall: 124-2770