greater estrogen receptor concentration

[ttweed@wildrockies.org (Tony Tweedale)]

old, but interesting, news.

E Dewailly et al. (CORRESPONDENCE): 'Could Rising levels of Estrogen
Receptor in Breast Cancer be due to Estrogenic Polllutants?' _J.NCI_
89:12:888-9 ('97)

reports that the rising breast cancer incidence is largely among
post-menopausal women and for estrogen receptor positive tumors, and on a
study that found the median level of estrogen receptors in breast tumors to
have increased steadily from 14 to 58 moles/mg of protein from '73 to
'92--independent of tumor size, patient age or assay method (Pujol et al
_Cancer_ 74:1601-6 ('94)).  Unamed O-Cl's were later shown to increase the
level of ER in MCF-7 cells (Soto et al.'The E-Screen Assay as a Tool...'
_EHP_ 103suppl.7:113-22 ('95)).  The correspondence authors also found a
D/R between p,p'-DDE in breast adipose and ER levels (r=0.52, adj. for
patient age and tumor size, n=18).

At the other end of the spectrum, Henderson et al. publish a letter (_JNCI_
89:11:818-9 ('97) propose decreasing age at time of first full-term
pregnancy as a cause for the increasing rate of testicular cancer..
Hypothesis is in-utero exposure to estrogen causes cryptorchidism
(undescended t.) and t. cancer.  The changes. in incidence of t. cancer
have paralled changes in mean age of 1st pregnancy (from 1910 it fell to
its lowest in 1940, and has increased some since then.  More avail.
estradiol circulates in the 1st trimester in the first pregn. than the 2nd,
apparantly.  Both t. cancer and cryptorchydism are associated w/ DES and w/
incr. nausea, and w/ obesity of mother (estrogen is an impt. factor in
appetite control and has a relationshp w/ nausea).  I guess aside from the
effcect of a first pregancy on testis, exogenous estrogen mimickers could
also explain the increase, though the close association between the 2
diseases and mean age of 1st pregn. bears looking into.

Tony Tweedale

Causality is a concept not subject to empirical demonstration. -David Hume
(1711-'76)

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