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How Carcinogens Cause Cancer
Siddhartha Mukherjee is the author of The Emperor of All Maladies: A Biography of Cancer, winner of the 2011 Pulitzer Prize in general nonfiction, and The Laws of Medicine. He is the editor of Best Science Writing 2013. Mukherjee is an assistant professor of medicine at Columbia University and a cancer physician and researcher. A Rhodes scholar, he graduated from Stanford University, University of Oxford, and Harvard Medical School. He has published articles in Nature, The New England Journal of Medicine, The New Yorker, The New York Times, and Cell. He lives in New York with his wife and daughters.
Siddhartha Mukherjee: So we’ve talked a little bit about the Cancer Genome. We’ve talked about the genetic changes, but I want to take one step back even before these genetic changes arise. Dr. Schwartzentruber, tell us what we know about how carcinogens cause cancer.
Doug Schwartzentruber: Well that is a challenging question because there are multiple ways for carcinogens to cause cancer and I probably should defer to some of the other panelists as well who have studied that much more than I have, but the obvious first step is how the environment which from the minute we’re born begins to interact and create feedback to say our normal cells that could then potentially be cancerous and maybe I'll stop at that point and lead into others.
Lewis Cantley: Well I can. I mean most carcinogens we think cause cancer by mutating DNA, but there are examples of carcinogens for example, forballesters [ph] which can cause skin cancers that almost certainly are to working through mutating DNA directly, although in the long run you always end up getting mutations in DNA. They are rather probably causing cells to grow at a higher rate and the higher the rate cells grow the more frequently they get mutations in DNA. Basically a cell has to go through a division cycle and make a daughter cell in order for a mutation to get locked in and that- But most really do it by directly damaging DNA, UV light, radiation directly damage the nucleotides in the DNA and many other chemical carcinogens interpolate into the DNA and at the time of cell division interfere with proper base replacement.
Harold Varmus: No, I agree entirely with this, but I would like to add two important points. First we as individuals grow up from a single cell and through many, many rounds of cell division many errors are going to occur because the ability to copy and distribute the three billion base pairs of DNA into daughter cells is an inherently error prone mechanism. We have ways to try to correct it, but nevertheless damage will occur and over the course of many cell doublings there will be damage that can be carcinogenic, so you don’t need to have external factors for cancer to arise. Cancer is probably part of our heritage. Genetic change is a good thing at the species level because we generate diversity throughout living systems.
The other point I would make is that not all carcinogens are UV light or radiation. Some of them are viruses and it’s very important to keep that in mind. It has been estimated that in developing countries for example maybe a third of cancers are caused by viruses. We actually have vaccines that are effective against some of those viruses. The human papillomavirus vaccine, the human hepatitis B virus vaccine can prevent a very large amount of cancer in those countries if the vaccines are made available, brought to patients, made affordable in poor countries. Cervical cancer is largely controlled in this country by pap smears, by early detection, and we only have about 3,000 deaths a year in this country, but in many parts of the world, India for example, and large parts of Africa, cervical cancer is the most common cause of death from cancer among women, and we now have the potential to reduce the incidence of that cancer by two-thirds using the human papillomavirus vaccine.
Seemingly every year there are new reports that something we consume or use on a daily basis is carcinogenic. But what exactly does that mean on a biological level?
Researchers are using technology to make visual the complex concepts of racism, as well as its political and social consequences.
- Often thought of first as gaming tech, virtual reality has been increasingly used in research as a tool for mimicking real-life scenarios and experiences in a safe and controlled environment.
- Focusing on issues of oppression and the ripple affect it has throughout America's political, educational, and social systems, Dr. Courtney D. Cogburn of Columbia University School of Social Work and her team developed a VR experience that gives users the opportunity to "walk a mile" in the shoes of a black man as he faces racism at three stages in his life: as a child, during adolescence, and as an adult.
- Cogburn says that the goal is to show how these "interwoven oppressions" continue to shape the world beyond our individual experiences. "I think the most important and powerful human superpower is critical consciousness," she says. "And that is the ability to think, be aware and think critically about the world and people around you...it's not so much about the interpersonal 'Do I feel bad, do I like you?'—it's more 'Do I see the world as it is? Am I thinking critically about it and engaging it?'"
President Vladimir Putin announces approval of Russia's coronavirus vaccine but scientists warn it may be unsafe.
A new coronavirus vaccine on display at the Nikolai Gamaleya National Center of Epidemiology and Microbiology in Moscow, Russia.
Credit: Alexander Zemlianichenko Jr/ Russian Direct Investment Fund via AP
Medical workers draw blood from volunteers participating in a trial of a coronavirus vaccine at the Budenko Main Military Hospital outside Moscow, Russia.
Credit: Russian Defense Ministry Press Service via AP
A scientist in Sweden makes a controversial presentation at a future of food conference.
- A behavioral scientist from Sweden thinks cannibalism of corpses will become necessary due to effects of climate change.
- He made the controversial presentation to Swedish TV during a "Future of Food" conference in Stockholm.
- The scientist acknowledges the many taboos this idea would have to overcome.
Depiction of cannibalism in the Medieval ages.
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A report from the New York Times raises questions over how the teletherapy startup Talkspace handles user data.
- In the report, several former employees said that "individual users' anonymized conversations were routinely reviewed and mined for insights."
- Talkspace denied using user data for marketing purposes, though it acknowledged that it looks at client transcripts to improve its services.
- It's still unclear whether teletherapy is as effective as traditional therapy.
Talkspace.com<p>Former employees also questioned the legitimacy of certain interventions by the company into client-therapist interactions. For example, after one therapist sent a client a link to an online anxiety worksheet, a company representative instructed her to try to keep clients inside the app.</p><p style="margin-left: 20px;">"I was like, 'How do you know I did that?'" Karissa Brennan, a therapist who worked with Talkspace from 2015 to 2017, told the Times. "They said it was private, but it wasn't."</p><p>Other former employees said the company would pay special attention to its "enterprise partner" clients, who worked at companies like Google. One therapist said Talkspace contacted her for taking too long to respond to Google clients.</p><p>Talkspace responded to the Times with a Medium <a href="https://medium.com/@founders_22883/talkspace-founders-respond-to-a-new-york-times-article-78d6f5c45c59" target="_blank">post</a>, which claimed the Times report contained false and "uninformed assertions."</p><p style="margin-left: 20px;">"Talkspace is a HIPAA/HITECH and SOC2 approved platform, audited annually by external vendors, and has deployed additional technologies to keep its data safe, exceeding all existing regulatory requirements," the post states.</p>