What Is Cancer?

Dr. Siddhartha Mukherjee: The term cancer covers over 100 different diseases. Starting with the biological definition what is cancer, what characteristics do these diseases share, Harold?

Dr. Harold Varmus: Well cancer is indeed a disease that can arise in virtually any of our tissues and virtually every cancer that arises is somewhat different from another, but there are commonalities and the most obvious is the fact that cancer represents a derangement of growth. Cells grow too much and they grow in antisocial ways. They cross normal tissue boundaries. They invade. They can grow in other places where they shouldn’t be growing. They often fail to differentiate the way normal cells will. There are my characteristics of cancer cells that have been identified in different tissues in which cancers arise, but the basic finding is a derangement of growth and a derangement of the normal ability of cells to stay in the places where they should be growing.

Dr. Siddhartha Mukherjee: Recently there has been an enormous degree of research on cancer. Has this definition begun to change of what cancer is?

Dr. Harold Varmus: The definition hasn’t so much changed, but the- but we’ve enlarged our sense of what cancer is about and we understand a great deal more about the basic mechanism that drives cells to behave inappropriately, to grow too much, to fail to die, to fail to differentiate, to fail to respond to signals all around cells that normally tell them to restrict growth and we now understand that many of those failures that cells exhibit when they become cancerous can be traced to mutations or to changes in the way genes are expressed, so we’ve enlarged dramatically our sense of what cancers are and we’ve changed our means of defining a cancer. A cancer is not simply a lung cancer. It doesn’t simply have a certain kind of appearance under the microscope or a certain behavior, but it also has a set of changes in the genes or in the molecules that modify gene behavior that allows us to categorize cancers in ways that is very useful in thinking about new ways to control cancer by prevention and treatment.

Dr. Lewis Cantley: Yeah, I can expand a little bit on that. So we say there is a hundred different cancers. That is based on pathology, what you can see in a microscope and even back in the 60s pathologists began to do what we now call molecular pathology. They don’t just look- stay in the tissue and look at it by eye. They look at chromosomes for example and so leukemia has broke out from a single leukemia to dozens of leukemias that are defined differentially based on what chromosomal change can be seen in a microscope and so we’re now taking it to an even deeper level where we can go in and sequence the entire genome of the cancer and these mutations keep giving us more and more subtypes, so breast cancer is going to be hundreds if not thousands of subtypes of breast cancers once we get to the actual molecular events that are going on, so it’s I think in a way this is good. It’s bad, but it’s good and the good thing about it is it kind of explains why no one type of cancer gets completely cured by a given drug or it’s relatively rare. You have some cured, some are not. They probably don’t really have the exact same disease and our previous classifications were not really detailed enough, so we can use the approach of divide and conquer, but it also means we need many more therapies than we currently have. 

Dr. Harold Varmus: It’s probably good to understand though that while the subdivision is absolutely correct and every cancer has its signature there are commonalities and in many cases you can say yes there are hundreds of different cancer types that look the same. They look different genetically, but frequently there are commonalities that can be points of attack, mutations that act as drivers of the cancer behavior.

Dr. Lewis Cantley: Yeah, so hopefully we won’t need a thousand treatments. 

One in three Americans are diagnosed in their lifetime with cancer, a derangement of normal cell growth in which cells grow in antisocial ways, crossing natural tissue boundaries.

What we want from horror is a cardiac jump-start, study suggests

A study looks at the ingredients of a good scare.

Credit: Nathan Wright/Unsplash
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    Credit: T. Masterson and the American Meteor Society | Robert Ward
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    This is what aliens would 'hear' if they flew by Earth

    A Mercury-bound spacecraft's noisy flyby of our home planet.

    Image source: sdecoret on Shutterstock/ESA/Big Think
    Surprising Science
    • There is no sound in space, but if there was, this is what it might sound like passing by Earth.
    • A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
    • Yes, in space no one can hear you scream, but this is still some chill stuff.

    First off, let's be clear what we mean by "hear" here. (Here, here!)

    Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.

    All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.

    BepiColombo

    Image source: European Space Agency

    The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.

    Into and out of Earth's shadow

    In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.

    The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."

    In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."

    When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.

    Magentosphere melody

    The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.

    BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.

    MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.

    Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.

    Should facial recognition software be banned on college campuses?

    A heated debate is occurring at the University of Miami.

    Credit: asiandelight / Adobe Stock
    Technology & Innovation
    • Students say they were identified with facial recognition technology after a protest at the University of Miami; campus police claim this isn't true.
    • Over 60 universities nationwide have banned facial recognition; a few colleges, such as USC, regularly use it.
    • Civil rights groups in Miami have called for the University of Miami to have talks on this topic.

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