Insulin-like growth factor 1 implicated in prostate cancer
BOSTON, MASSACHUSETTS. An international team of researchers from the Harvard
Medical School, the University of Athens, and the Karolinska Institute in Sweden
report that high levels of insulin-like growth factor 1 (IGF-1) in the blood are
associated with an increased risk of prostate cancer. Their study involved 52
men with confirmed prostate cancer, 52 men with benign prostatic hyperplasia
(BPH - enlarged prostate gland) and 52 healthy controls. Analysis of blood
samples from the study participants showed that increased levels of IGF-1
corresponded to higher risks of prostate cancer. An increment of 60 nanograms
of IGF-1 per milliliter of blood corresponded to an almost two-fold increase in
the risk of prostate cancer. No relationship was found between IGF-1 levels and
the risk of having an enlarged prostate. High levels of circulating
testosterone were also associated with a higher risk of prostate cancer while
higher levels of dehydroepiandrosterone sulphate (DHEAS) were associated with
increased incidence of BPH. Although the researchers do not rule out that
prostate cancer in itself could increase IGF-1 levels they nevertheless conclude
that high IGF-1 levels may promote prostate cancer, but do not increase the risk
of BPH. They also point out that previous research found a significant
correlation between high IGF-1 levels and the incidence of breast cancer in
women. NOTE: This study was partially funded by Monsanto, the manufacturer of
bovine growth hormone (BST, Posilac). Milk from BST-treated cows has been found
to contain much higher levels of IGF-1 than does normal milk.
Mantzoros, C.S., et al. Insulin-like growth factor 1 in relation to prostate
cancer and benign prostatic hyperplasia. British Journal of Cancer, Vol. 76,
No. 9, 1997, pp. 1115-18
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