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A Reaction: Breast Cancer’s Evolution

Published on | Kylie Chin

TED and the Huffington Post have started TEDWeekends, which includes programming and articles nested around a recent TEDTalk. If you’re not familiar with TED, here’s a link to catch you up. 

Earlier this month Louise Leaky delivered her talk entitled: Is the Human Race In Danger Of Becoming Extinct Soon? You can watch the speech here.

What’s interesting is, well, the entire talk is actually extremely compelling stuff, but how it relates to breast cancer was surmised beautifully by Marisa Weiss, M.D. in reaction to the TEDTalk. Here’s a link to that as well – but we’ll do our best to summarize for you below.

First off, some statistics and the discrepancies that Weiss noticed.

  • 29% of all cancers begin in the breast, more than any other type of cancer
  • Only 10% of breast cancers are due to specific inherited high risk genes
  • 90% are mostly triggered by environmental and lifestyle factors

So with that in mind, Weiss asks herself

“Why the breast is the favorite place for cancer to occur in a woman’s body?”

Weiss breaks it down into three contributing outside factors that seem to cause breasts to be susceptible to develop cancer: biological, evolutionary, and chemical.

Biological Factors

Breasts develop much more slowly, years behind other organs. Creating an organ is an extremely delicate process and each time the body creates a new batch of DNA to pass along to a nascent crop of baby cells, mutations can occur if the operation is disrupted. Weiss poses the example: “[…] exposing an adolescent girl to radiation at the critical time she’s building her breast tissue can lead to permanent gene mutations that increase her risk for breast cancer later in life.”

Another biological factors surrounds the ‘waiting mode’ that breasts are trapped in until full-term pregnancy and breast-feeding. Organs that have a specific job to do from birth like the brain, heart or kidneys, have a much lower risk of cancer.

Evolutionary Factors

No hyperbole here – the survival of the species depends on feeding its young, making the breast critical to the perpetuation of the human race. Heavy stuff, right? Let’s back up a little; a special evolutionary feature of breast cells involves estrogen receptors. As estrogen is received it signals the breasts when it’s time to grow, the problem is the estrogen receptor has the capacity to interact with many substances that can resemble estrogen—rather than responding to the estrogen itself. While this flexibility may have had an evolutionary purpose of ensuring milk could be produced under harsh circumstances—it also makes the breast more vulnerable to breast cancer in our modern day world.

Chemical Factors

Compare the chemicals in the working and living conditions to 100 years ago and you’ll see an explosion of:

  • bisphenol A (plastics, food can liners, cashier receipts)
  • phthalates (personal care products)
  • flame retardants (in mattresses, kids’ pajamas, upholstery)
  • hormones in food (given to beef and dairy cattle)
  • pharmaceutical hormones (birth control pills and hormone replacement therapy)

Weiss is not saying that each of these directly contribute to breast cancer. However, she does surmise “These chemicals are very new to our environment and to our bodies in evolutionary terms. One hundred years ago, they didn’t exist and breast cancer was a relatively uncommon disease.”

Weiss goes on to conclude her reaction piece to the TEDTalk with:

“So what was intended as an evolutionary advantage has turned into a curse of modern life, contributing to a significantly higher incidence of breast cancer. While our bodies have not yet evolved to counter these assaults, our thinking must. We need to do a much better job of recognizing this evolutionary vulnerability and protecting girls and women from its effects.”

We’d love to hear your thoughts and opinions in the comments below!

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