153 research outputs found
Oestrogen receptors and prolactin in rat mammary tumour development
Mammary cancer has been a challenge to researchers for
many years, because of the continuous menace of this disease
to (wo)mankind. Since it is difficult to study the mechanism
of mammary gland carcinogenesis experimentally in the human,
model systems had to be devised. "Spontaneous" mammary
tumours in rats are quite rare, or occur only after a very
long period (Burek & Hollander, 1977; Burek, 1978). Therefore,
induction of tumours has been used to obtain large
amounts of tumour tissue. Two tumour model systems which are
relevant to the work presented in this thesis will be
described in some detail
Heritability of reproductive hormones in adult male twins
Background: Proper functioning of the male reproductive axis depends on complex feedback systems between several hormones. In this study, the genetic contribution of various endocrine components of the hypothalamic-pituitary-testicular axis is evaluated and previously observed differences in FSH and inhibin B levels between mono- (MZ) and dizygotic (DZ) twins are re-investigated. Methods: Inhibin B, FSH, LH, sex hormone-binding globulin (SHBG) and testosterone levels were assayed in 128 adult males (20 MZ twin pairs, 7 single MZ twins, 10 DZ twin pairs, 27 single DZ twins and 34 siblings of twins, constituting 10 sibling pairs), aged 15.6-68.7 years. Hormone levels were compared across zygosity groups and heritability estimates were obtained using maximum likelihood variance component analysis. Results: Heritability estimates ranged from 56% (testosterone) to 81% (inhibin B and SHBG). For LH and FSH, the heritability was estimated at 68% and 80% respectively. No mean differences in hormone levels were observed across groups. Conclusions: All measured hormones are highly heritable. A difference in the FSH-inhibin B feedback system between DZ twin males and MZ twin males could not be confirmed. © The Author 2007. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved
Pooled analysis of prognostic impact of urokinase-type plasminogen activator and its inhibitor PAI-1 in 8377 breast cancer patients
BACKGROUND: Urokinase-type plasminogen activator (uPA) and its inhibitor
(PAI-1) play essential roles in tumor invasion and metastasis. High levels
of both uPA and PAI-1 are associated with poor prognosis in breast cancer
patients. To confirm the prognostic value of uPA and PAI-1 in primary
breast cancer, we reanalyzed individual patient data provided by members
of the European Organization for Research and Treatment of Cancer-Receptor
and Biomarker Group (EORTC-RBG). METHODS: The study included 18 datasets
involving 8377 breast cancer patients. During follow-up (median 79
months), 35% of the patients relapsed and 27% died. Levels of uPA and
PAI-1 in tumor tissue extracts were determined by different immunoassays;
values were ranked within each dataset and divided by the number of
patients in that dataset to produce fractional ranks that could be
compared directly across datasets. Associations of ranks of uPA and PAI-1
levels with relapse-free survival (RFS) and overall survival (OS) were
analyzed by Cox multivariable regression analysis stratified by dataset,
including the following traditional prognostic variables: age, menopausal
status, lymph node status, tumor size, histologic grade, and steroid
hormone-receptor status. All P values were two-sided. RESULTS: Apart from
lymph node status, high levels of uPA and PAI-1 were the strongest
predictors of both poor RFS and poor OS in the analyses of all patients.
Moreover, in both lymph node-positive and lymph node-negative patients,
higher uPA and PAI-1 values were independently associated with poor RFS
and poor OS. For (untreated) lymph node-negative patients in particular,
uPA and PAI-1 included together showed strong prognostic ability (all
P<.001). CONCLUSIONS: This pooled analysis of the EORTC-RBG datasets
confirmed the strong and independent prognostic value of uPA and PAI-1 in
primary breast cancer. For patients with lymph node-negative breast
cancer, uPA and PAI-1 measurements in primary tumors may be especially
useful for designing individualized treatment strategies
Urinary sex hormone excretions in premenopausal women and coronary heart disease risk: a nested case-referent study in the DOM-cohort
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