Self-Motivation
David Goggins
Former Navy Seal
Career Development
Bryan Cranston
Actor
Critical Thinking
Liv Boeree
International Poker Champion
Emotional Intelligence
Amaryllis Fox
Former CIA Clandestine Operative
Management
Chris Hadfield
Retired Canadian Astronaut & Author
Learn
from the world's big
thinkers
Start Learning

Why Cancer Attacks Some Tissues—And Not Others

Dr. Siddhartha MukherjeeAs you mentioned there are some parts of the body, some tissues where cancer is more infrequent and other tissues where cancer is more frequent.  Dr. Schrag, give us a sense of why cancer often occurs in certain tissues and rarely occurs in other tissues. 

Dr. Deborah Schrag: You know we don’t know the answer to that.  We do certainly know that lifestyle factors are extremely important and have an enormous influence in terms of where cancers occur, so we know that exposure to hormones and the hormonal environment that people are exposed makes an enormous difference.  This is true for breast cancer, prostate cancer.  These remain two of the most common cancers among men and women.  Of course smoking is also- remains an important issue.  Now we know that we can’t- if we could modify folks lifestyle factors we would not be able to eradicate cancer, but just as Dr. Varmus was talking about how there are certain commonalities, there are certain common molecular mechanisms that go awry frequently, certain key patterns.  We also know that with respect to behaviors, lifestyle, exposure there is certain commonalities, not enough exercise, too many calories and we have to work to exploit these and we really have to work to understand the interactions between the molecular events at the cellular level and the environmental exposures and lifestyle choices people make and how these factors interact.

Dr. Harold Varmus:  Could I just add one point to that?  The question you raised about some organs not having cancers.  For example, the heart, that is what I would call a provocative question.  Why shouldn’t there be a cancer there and it leads you to think about what cells in any organ are at risk of cancers and it’s very likely that the incidence of cancer in different tissue types, prostate versus heart for example, virtually every adult male at the age of 90 having some prostate cancer and heart cancers being virtually unheard of probably reflects how many cells are at risk of becoming a cancer in any single organ and the likelihood that those cells are exposed to some kind of oncogenic stress, whether it’s tobacco smoke or hormonal influence such as Debbie is referring to, but to me the remarkable variation not just among organs, but among organ types in different environmental settings, different locations represent one of the great challenges that I don’t think the cancer community has completely grappled with yet and to me this is an area of provocative research that we ought to be paying more attention to now that we have better tools for looking at genetics.

Deborah Schrag: So an interesting example that comes up for me all that time that I just don’t understand.  We’re all born with 25 feet of small intestine, but yet we see only fewer than 5,000 cases a year in the United States.

Siddhartha Mukherjee: Contrast that with the large intestine... 

Deborah Schrag:  We contrast that with colon cancer, which remains one of our top cancers.  Well you know there is 6 to 9 feet of large bowel and we have 150,000 cases per year.  When we look at these cells under the microscope it’s all epithelial cells.  I mean an intestinal cell in the small intestine and in the large intestine is molecularly not that different.  The large bowel cells are a little bit more engaged in reabsorbing water than they are in reabsorbing nutrients, but we do not understand why there is this dramatic difference between the incidence of cancer in the small bowel, which there is more of and the large bowel.  We haven’t answered that.

Harold Varmus:  It brings up a very interesting new theme in cancer research.  What is the role of the microorganisms we carry around with us?  What is now being called the microbiome and of course the large intestine has trillions of bacteria and the small intestine has much less.  That may well be that that is a driver of oncogenic change and of course the small intestine tumors, many of which you- as you mentioned, there are some.  They are very frequently sarcomas, that is cancers of connective tissue as opposed to being epithelial and that is a very interesting example of that contrast.

Dr. Harold Varmus: Why do virtually all men over the age of 90 develop some amount of prostate cancer whereas heart cancer is practically unheard of?

LIVE EVENT | Radical innovation: Unlocking the future of human invention

Innovation in manufacturing has crawled since the 1950s. That's about to speed up.

Big Think LIVE

Add event to calendar

AppleGoogleOffice 365OutlookOutlook.comYahoo


Keep reading Show less

Self-driving cars to race for $1.5 million at Indianapolis Motor Speedway ​

So far, 30 student teams have entered the Indy Autonomous Challenge, scheduled for October 2021.

Indy Autonomous Challenge
Technology & Innovation
  • The Indy Autonomous Challenge will task student teams with developing self-driving software for race cars.
  • The competition requires cars to complete 20 laps within 25 minutes, meaning cars would need to average about 110 mph.
  • The organizers say they hope to advance the field of driverless cars and "inspire the next generation of STEM talent."
Keep reading Show less

The dangers of the chemical imbalance theory of depression

A new Harvard study finds that the language you use affects patient outcome.

Image: solarseven / Shutterstock
Mind & Brain
  • A study at Harvard's McLean Hospital claims that using the language of chemical imbalances worsens patient outcomes.
  • Though psychiatry has largely abandoned DSM categories, professor Joseph E Davis writes that the field continues to strive for a "brain-based diagnostic system."
  • Chemical explanations of mental health appear to benefit pharmaceutical companies far more than patients.
Keep reading Show less

NASA's idea for making food from thin air just became a reality — it could feed billions

Here's why you might eat greenhouse gases in the future.

Jordane Mathieu on Unsplash
Technology & Innovation
  • The company's protein powder, "Solein," is similar in form and taste to wheat flour.
  • Based on a concept developed by NASA, the product has wide potential as a carbon-neutral source of protein.
  • The man-made "meat" industry just got even more interesting.
Keep reading Show less

Navy SEALs: How to build a warrior mindset

SEAL training is the ultimate test of both mental and physical strength.

Videos
  • The fact that U.S. Navy SEALs endure very rigorous training before entering the field is common knowledge, but just what happens at those facilities is less often discussed. In this video, former SEALs Brent Gleeson, David Goggins, and Eric Greitens (as well as authors Jesse Itzler and Jamie Wheal) talk about how the 18-month program is designed to build elite, disciplined operatives with immense mental toughness and resilience.
  • Wheal dives into the cutting-edge technology and science that the navy uses to prepare these individuals. Itzler shares his experience meeting and briefly living with Goggins (who was also an Army Ranger) and the things he learned about pushing past perceived limits.
  • Goggins dives into why you should leave your comfort zone, introduces the 40 percent rule, and explains why the biggest battle we all face is the one in our own minds. "Usually whatever's in front of you isn't as big as you make it out to be," says the SEAL turned motivational speaker. "We start to make these very small things enormous because we allow our minds to take control and go away from us. We have to regain control of our mind."
Keep reading Show less
Quantcast