International Agency for Research on Cancer (IARC) - Summaries & Evaluations
OESTRADIOL-17b
VOL.: 6 (1974) (p. 99)
5. Summary of Data Reported and Evaluation
(N.B.: This section should be read in conjunction with the section
'
General Conclusions on Hormones'.)
5.1 Animal carcinogenicity data
Oestradiol-17b was tested in mice, rats, hamsters and guinea-pigs
by subcutaneous injection or implantation. Its administration resulted
in an increased incidence of mammary, pituitary, uterine, cervical,
vaginal and lymphoid tumours and interstitial-cell tumours of the
testis in mice. In rats, there was an increased incidence of mammary
and pituitary tumours. In hamsters, malignant kidney tumours occurred
with a high incidence in intact or castrated males and in
ovariectomized but not in intact females. In guinea-pigs, diffuse
fibromyomatous abdominal lesions of uncertain histological
interpretation were observed. Subcutaneous injections in neonatal mice
resulted in precancerous and cancerous vaginal lesions in later life.
The studies in monkeys could not be assessed since they were limited
in group size and duration.
Oestradiol-17b treatment increased the incidence of mammary and
pituitary tumours in strains of mice having a spontaneous incidence of
these tumours. The spontaneous occurrence can be related either to the
presence of a virus or to a particular genetic susceptibility. No
evidence of the possible role of a virus has been ascertained for
rats.
The role of the hormonal balance in the development and persistence of
these tumours and possible synergisms with other carcinogenic factors
in increasing the incidence of lymphoid tumours has been discussed
(see section, "General Remarks on the Sex Hormones", in this volume).
5.2 Human carcinogenicity data
No case reports or epidemiological studies were available to the
Working Group. Epidemiological studies on steroid hormones used in
oestrogen treatment have been summarized in the section, "Oestrogens
and Progestins in Relation to Human Cancer" in this volume.
Subsequent evaluations: Vol. 21 (1979);
Suppl. 7 (1987)
Last updated: 18 March 1998