Let’s talk about the first hallmark of cancer. The highlighted section of the graphic says “sustained proliferative signaling”. What in the world does that mean? Earlier in this post, I said that normal cells know when to grow and divide and when to die. The mechanisms by which these cells know how to do this are very detailed and complicated, but generally the ‘permission’ to grow must come from another cell (you can’t write your own pass to grow). A very simplified version of this would be that Cell A receives a signal called a growth factor from Cell X. After Cell A receives the signal, a ‘grow’ switch is flipped to ON and Cell A grows and divides until the switch is flipped off (either from another signal or by virtue it only stays on for a certain period of time).
Remember how I spoke about my old friend the Epstein Barr Virus (EBV) here? Well,EBV generally infects B cells which are part of the immune system. Like many viruses, EBV hijacks the machinery of a normal cell to do its dirty work. During the hijack and hostage situation, EBV can mess around with the normal B cell’s DNA and get one of the ‘grow’ switches called the MYC gene permanently stuck in the ON position, and thus it doesn’t need to rely on Cell X to get a signal to grow because the MYC gene is permanently flipped to ON (and so will all of the copies it makes of itself). Hence, this is one way that EBV contributes to cancer development, particularly in some B cell lymphomas such as Burkitt’s Lymphoma or Hodgkin’s Lymphoma.
That is the most simplified way I can explain this hallmark, but cancer cells also have other sneaky ways to bypass the rule that the ‘permission to grow’ has to be regulated and come from another source. Sometimes cancer cells find a way to covertly secrete their own growth factors and they signal more cancer cells to grow and it becomes a vicious cycle. I think of this as a gremlin getting wet …the water is the growth factor and the bad gremlins that spawn from it are new cancer cells. The bad gremlins have figured out how to throw more water (growth factors) at each other and pretty soon the room is full of bad gremlins and a nasty tumor has formed (Seriously, I really hope I’m not the only one who gets this analogy because it may mean I am old).
Lastly, cancer cells can change how much growth factor is needed to flip the switch to ON so that smaller amounts of growth factor are needed to trigger the ‘grow’ response. This is the exact opposite of what happens to me with caffeine. I need more and more caffeine to get the same awake response…but that’s a whole different New Year’s Resolution…
There you have it, my best attempt to explain Hallmark #1. #morethanfour #ChildhoodCancer365
Full paper can be found here: Hallmarks of Cancer: The Next Generation
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