Oestrogen receptor activity and endocrine status in DMBA-induced rat mammary tumours

Hawkins, R. A.; Hill, Adam T.; Freedman, B.; Killen, E.; Buchan, Peter; Miller, William R.; Forrest, A. P. M.

doi:10.1016/0014-2964(77)90208-0

Cited by 19 publications

(9 citation statements)

References 22 publications

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“…In agreement with our earlier findings (Hawkins et al 1977) the concentration of empty oestrogen receptor sites detected in 20 DMBA-induced tumours was inversely correlated with the plasma oestradiol-17ß concentration in the host at the time of tumour excision (Spearman's p= -0-53, P< 0-025).…”

Section: Lecithin Synthesissupporting

confidence: 91%

“…It has previously been shown that the stage in the oestrous cycle and/or the concen¬ tration of oestradiol-17ß in the plasma influences the level of empty oestrogen receptors available for detection (Hawkins et al 1977) and this has been confirmed in the present work. Elimination of both the DMBA-induced and transplanted tumours derived from rats in pro-oestrus or in a prolonged state of oestrus, with plasma oestradiol-17ß concen¬ trations in excess of 2-0 ng/100 ml, did not eliminate the overlap in oestrogen receptor levels between the tumour types.…”

Section: Sensitivity In Vitrosupporting

confidence: 80%

“…Oestrogen-receptor activity was determined by the method of Hawkins, Hill, Freedman, Killen, Buchan, Miller & Forrest (1977). In some experiments, a second animal was killed in a similar manner and the tumour was used for oestrogen-receptor assay only.…”

Section: Oestrogen-receptor Activitymentioning

confidence: 99%

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Synthesis of Dna and Lecithin in Tissue Culture and Oestrogen Receptor Activity in Rat Mammary Tumours Dependent on and Independent of the Ovary

Scott¹,

Murphy²,

Hawkins³

1979

Journal of Endocrinology

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Dimethylbenz(alpha)anthracene (DMBA)-induced and transplanted rat mammary tumours (2 lines) were examined for oestrogen receptor activity, and for sensitivity to hormones in vivo (by ovariectomy) and in vitro (by tissue culture). In vivo, the growth of all tumours induced by the administration of DMBA in random-bred Sprague-Dawley rats was found to be dependent on the ovary, whilst in all transplanted tumours (12 TG-3 and six TG-5 lines), maintained in an inbred strain of Sprague-dawley rats, growth was found to be independent of the ovary. In vitro, the capacity for DNA synthesis in DMBA-induced tumours was better maintained after 24 h when insulin (10 microgram/ml) and corticosterone (5 microgram/ml) or insulin, corticosterone and prolactin (each 5 microgram/ml) were present in the medium (five out of 12 and eight out of 11 tumours respectively); no effect of hormones in the media was detected after 48 h. In the transplanted tumours, no effect of hormones on DNA synthesis was detected after either 24 or 48 h of culture. Synthesis of lecithin was not detectably influenced by the presence of hormones in either DMBA-induced or transplanted tumours. Oestrogen receptor concentrations were, on average, significantly higher in the DMBA-induced tumours than in either line of transplanted tumour. For 22 DMBA-induced tumours and 15 transplanted tumours, the effect of hormones in vitro ('response') was directly correlated with receptor concentration at time 0 (Spearman's rho = +0.59) and inversely correlated with the rate of DNA synthesis ('basal') at time 0 (Spearman's rho = -0.62). No single parameter or pair of parameters permitted accurate distinction between the tumour types.

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Section: Lecithin Synthesissupporting

confidence: 91%

Section: Sensitivity In Vitrosupporting

confidence: 80%

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Synthesis of Dna and Lecithin in Tissue Culture and Oestrogen Receptor Activity in Rat Mammary Tumours Dependent on and Independent of the Ovary

Scott¹,

Murphy²,

Hawkins³

1979

Journal of Endocrinology

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“…Previous studies in patients with breast cancer (Taylor et al, 1982;Hamm & Allegra, 1988;Toma et al, 1986) and in experimental animals (Vignon & Rochefort, 1976;Hawkins et al, 1977b;Cho-Chung et al, 1978) have shown a decrease in receptor concentration after endocrine manipulation or, as in the present study, no consistant change (Hull et al, 1983;Mobbs et al, 1987). The conflicting results,in human breast cancer may derive from the inclusion of patients on tamoxifen (Taylor et al, 1982), which causes a marked apparent reduction in ER concentration (this study and Hull et al, 1983) or from the difficulties in comparing different tumour deposits (Taylor et al, 1982;Hamm & Allegra, 1988).…”

Section: Discussionmentioning

confidence: 99%

Does the oestrogen receptor concentration of a breast cancer change during systemic therapy?

Hawkins¹,

Tesdale²,

Anderson³

et al. 1990

Br J Cancer

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Summary The effect of systemic therapy on tumour oestrogen receptor (ER) concentration has been studied in 88 patients with large, operable, primary tumours (total 89) of the breast. In 26 patients, tumour was not available for study on one occasion (usually post-treatment). Forty-five patients were treated initially by endocrine therapy but, of these, 13 who had failed to respond went on to receive chemotherapy also. Seventeen patients with low concentrations of ER (<20 fmol mg-' protein) were treated directly by chemotherapy. Patients underwent an incisional biopsy for confirmation of diagnosis and determination of pre-treatment ER by radioligand binding assay, followed by systemic therapy for 3 months (or 6 months for both endocrine and cytotoxic therapies). Following 3 months of systemic therapy (6 months when patients received both endocrine and cytotoxic therapies), patients proceeded on to mastectomy and axillary lymphnode clearance. When residual tumour was present within the mastectomy specimen, a portion was selected for ER assay by the pathologist.In both pre-and post-treatment specimens, a section was cut from the face of the tissue portion used for receptor analysis, fixed in formol-saline and stained with haematoxylin and eosin to permit histopathological confirmation of the presence of tumour. Twenty-six patients in whom either the pre-or post-treatment specimen contained <10% tumour, as assessed by the pathologist, have been excluded from the Correspondence: R.A. Hawkins.

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“…Hawkins et al, 1977;Bayard et al, 1978). This study suggests that whilst the former effect may predominate in premenopausal women, where progesterone levels may determine oestrogen receptor synthesis (Saez et al, 1978), the latter effect may occur, to some extent, in postmenopausal subjects.…”

mentioning

confidence: 90%

Plasma oestrogens and oestrogen receptors in breast cancer patients

Mason¹,

Miller²,

Hawkins³

1985

Br J Cancer

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Oestrogen receptor activity and endocrine status in DMBA-induced rat mammary tumours

Cited by 19 publications

References 22 publications

Synthesis of Dna and Lecithin in Tissue Culture and Oestrogen Receptor Activity in Rat Mammary Tumours Dependent on and Independent of the Ovary

Synthesis of Dna and Lecithin in Tissue Culture and Oestrogen Receptor Activity in Rat Mammary Tumours Dependent on and Independent of the Ovary

Does the oestrogen receptor concentration of a breast cancer change during systemic therapy?

Plasma oestrogens and oestrogen receptors in breast cancer patients

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