Light at night, effect on Breast Cancer/Tamoxifen Resistance

lightandwind

http://www.medicalnewstoday.com/articles/280194.ph...

http://www.oncologynurseadvisor.com/exposure-to-di...

luv_gardening

Thanks for this Light.  I couldn't sign in to the second link so I searched for the study.  I assume this is the one:

Circadian and Melatonin Disruption by Exposure to Light at Night Drives Intrinsic Resistance to Tamoxifen Therapy in Breast Cancer

Friday 25 July 2014

Abstract

Resistance to endocrine therapy is a major
impediment to successful treatment of breast cancer. Preclinical and
clinical evidence
links resistance to antiestrogen drugs in breast
cancer cells with the overexpression and/or activation of various
pro-oncogenic
tyrosine kinases. Disruption of circadian rhythms
by night shift work or disturbed sleep-wake cycles may lead to an
increased
risk of breast cancer and other diseases. Moreover,
light exposure at night (LEN) suppresses the nocturnal production of
melatonin
that inhibits breast cancer growth. In this study,
we used a rat model of estrogen receptor (ERα⁺) MCF-7 tumor
xenografts to demonstrate how altering light/dark cycles with dim LEN
(dLEN) speed the development of breast
tumors, increasing their metabolism and growth and
conferring an intrinsic resistance to tamoxifen therapy. These
characteristics
were not observed in animals in which the circadian
melatonin rhythm was not disrupted, or in animals subjected to dLEN if
they received nocturnal melatonin replacement.
Strikingly, our results also showed that melatonin acted both as a tumor
metabolic
inhibitor and a circadian-regulated kinase
inhibitor to reestablish the sensitivity of breast tumors to tamoxifen
and tumor
regression. Together, our findings show how
dLEN-mediated disturbances in nocturnal melatonin production can render
tumors
insensitive to tamoxifen. Cancer Res; 74(15); 1–12. ©2014 AACR.

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I hope melatonin does reverse this effect as stated at the end. 

I use a mask at night but never found a way to black out light around the nose and it slips up sometimes in the night.  Keeping the room dark is hard.