How do cancer cells behave differently from healthy ones? - George Zaidan
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0:14 - 0:17We all start life as one single cell.
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0:17 - 0:20Then that cell divides and we are two cells,
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0:20 - 0:21then four,
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0:21 - 0:22then eight.
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0:22 - 0:23Cells form tissues,
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0:23 - 0:24tissues form organs,
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0:24 - 0:26organs form us.
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0:26 - 0:29These cell divisions, by which we go from a single cell
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0:29 - 0:31to 100 trillion cells,
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0:31 - 0:33are called growth.
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0:33 - 0:35And growth seems like a simple thing
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0:35 - 0:36because when we think of it,
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0:36 - 0:38we typically think of someone getting taller
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0:38 - 0:40or, later in life, wider,
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0:40 - 0:43but to cells, growth isn't simple.
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0:43 - 0:45Cell division is an intricate chemical dance
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0:45 - 0:48that's part individual, part community-driven.
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0:48 - 0:50And in a neighborhood of 100 trillion cells,
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0:50 - 0:53some times things go wrong.
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0:53 - 0:57Maybe an individual cell's set of instructions, or DNA,
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0:57 - 0:58gets a typo,
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0:58 - 1:00what we call a mutation.
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1:00 - 1:02Most of the time, the cell senses mistakes
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1:02 - 1:03and shuts itself down,
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1:03 - 1:05or the system detects a troublemaker
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1:05 - 1:06and eliminates it.
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1:06 - 1:09But, enough mutations can bypass the fail-safes,
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1:09 - 1:11driving the cell to divide recklessly.
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1:11 - 1:13That one rogue cell becomes two,
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1:13 - 1:14then four,
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1:14 - 1:15then eight.
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1:15 - 1:17At every stage, the incorrect instructions
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1:17 - 1:20are passed along to the cells' offspring.
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1:20 - 1:21Weeks, months, or years
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1:21 - 1:24after that one rogue cell transformed,
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1:24 - 1:27you might see your doctor about a lump in your breast.
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1:27 - 1:28Difficulty going to the bathroom could reveal
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1:28 - 1:30a problem in your intestine,
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1:30 - 1:31prostate,
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1:31 - 1:32or bladder.
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1:32 - 1:35Or, a routine blood test might count too many white cells
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1:35 - 1:37or elevated liver enzymes.
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1:37 - 1:39Your doctor delivers the bad news:
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1:39 - 1:40it's cancer.
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1:40 - 1:41From here your strategy will depend
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1:41 - 1:43on where the cancer is and
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1:43 - 1:45how far it's progressed.
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1:45 - 1:48If the tumor is slow-growing and in one place,
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1:48 - 1:50surgery might be all you need, if anything.
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1:50 - 1:53If the tumor is fast-growing or invading nearby tissue,
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1:53 - 1:55your doctor might recommend radiation
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1:55 - 1:58or surgery followed by radiation.
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1:58 - 1:59If the cancer has spread,
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1:59 - 2:02or if it's inherently everywhere like a leukemia,
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2:02 - 2:05your doctor will most likely recommend chemotherapy
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2:05 - 2:07or a combination of radiation and chemo.
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2:07 - 2:09Radiation and most forms of chemo work
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2:09 - 2:12by physically shredding the cells' DNA
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2:12 - 2:15or disrupting the copying machinery.
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2:15 - 2:19But neither radiation nor chemotherapeutic drugs target only cancer cells.
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2:19 - 2:22Radiation hits whatever you point it at,
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2:22 - 2:24and your blood stream carries chemo-therapeutics
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2:24 - 2:26all over your body.
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2:26 - 2:29So, what happens when different cells get hit?
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2:29 - 2:30Let's look at a healthy liver cell,
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2:30 - 2:31a healthy hair cell,
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2:31 - 2:33and a cancerous cell.
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2:33 - 2:36The healthy liver cell divides only when it is stressed;
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2:36 - 2:38the healthy hair cell divides frequently;
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2:38 - 2:42and the cancer cell divides even more frequently and recklessly.
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2:42 - 2:44When you take a chemotherapeutic drug,
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2:44 - 2:46it will hit all of these cells.
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2:46 - 2:49And remember that the drugs work typically by disrupting cell division.
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2:49 - 2:51So, every time a cell divides,
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2:51 - 2:54it opens itself up to attack,
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2:54 - 2:56and that means the more frequently a cell divides,
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2:56 - 2:58the more likely the drug is to kill it.
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2:58 - 3:00So, remember that hair cell?
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3:00 - 3:03It divides frequently and isn't a threat.
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3:03 - 3:05And, there are other frequently dividing cells in your body
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3:05 - 3:08like skin cells, gut cells, and blood cells.
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3:08 - 3:11So the list of unpleasant side effects of cancer treatment
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3:11 - 3:13parallels these tissue types:
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3:13 - 3:14hair loss,
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3:14 - 3:15skin rashes,
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3:15 - 3:15nausea,
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3:15 - 3:16vomiting,
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3:16 - 3:16fatigue,
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3:16 - 3:17weight loss,
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3:17 - 3:19and pain.
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3:19 - 3:22That makes sense because these are the cells that get hit the hardest.
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3:22 - 3:25So, in the end, it is all about growth.
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3:25 - 3:27Cancer hijacks cells' natural division machinery
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3:27 - 3:30and forces them to put the pedal to the metal,
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3:30 - 3:32growing rapidly and recklessly.
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3:32 - 3:34But, using chemotherapeutic drugs,
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3:34 - 3:36we take advantage of that aggressiveness,
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3:36 - 3:38and we turn cancer's main strength
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3:38 - 3:40into a weakness.
- Title:
- How do cancer cells behave differently from healthy ones? - George Zaidan
- Speaker:
- George Zaidan and Charles Morton
- Description:
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View full lesson: http://ed.ted.com/lessons/how-do-cancer-cells-behave-differently-from-healthy-ones-george-zaidan
How do cancer cells grow? How does chemotherapy fight cancer (and cause negative side effects)? The answers lie in cell division. George Zaidan explains how rapid cell division is cancer's "strength" -- and also its weakness.
Lesson by George Zaidan, animation by TED-Ed.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 03:51
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