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Video transcript

so now we can talk about the different types of acute leukemias and remember that acute leukemias come from these cells so the most immature types of blood cells that you can possibly have and we can split up the acute leukemias into ones that come from myeloid cells so these cells so that acute myeloid leukemias or the leukemias that come from lymphoid cells so the acute lymphoid leukemias and we're going to start off by talking about the acute lymphoid leukemias so I took that big diagram and I shrunk it down and I stuck it into the corner because to be completely honest nobody memorizes this diagram by just looking at it one or two times you have to keep looking at it over and over again in order for it to stick inside your mind so if at any point you're like what cell is she talking about just look about this diagram to help you reorient yourself so I said that we were going to start off talking about these guys so the acute lymphoblastic leukemias that's often abbreviated áall so we don't have to write it all out again so one of the things that I really loved about learning the different leukemias was that the name of the Leukemia told you a lot of the information that you needed to know about it so the word leukemia tells you that you're dealing with a cancer of the blood cells well what type of blood cells so this is a lymphoblastic leukemia so we're dealing with lymphoblasts or immature lymphocytes immature B and T cells and just how immature are those cells so if this is an acute leukemia we're dealing with the most immature cells that you could possibly have and really that's a majority of the information that you need to know about this disease a couple of other important things is number one áall is the most common cancer in kids so unfortunately it affects the little ones the most and it's also associated with Down syndrome with Down syndrome and you may know that Down syndrome is a genetic syndrome where you end up with three copies of chromosome 21 and in a normal cell you only have two copies of chromosome 21 but in Down syndrome you end up with an extra copy so you end up with three in total and that's called trisomy 21 well it turns out that chromosome 21 has this gene on it and that gene makes a protein that can damage DNA so the idea is among other ideas that because you have an extra gene you end up with more damage to your DNA and that increases your risk of getting a ll so let's say that you have a patient a really young patient who's showing signs and symptoms of leukemia so you go ahead and you get a bone marrow aspiration from him and if the patient has a ll you'd expect that when you looked at the aspirate underneath the microscope you see lots of lymphoblasts because ll after all is just a cancer of lymphoblasts right but what do I mean by you'd see a lot of lymphoblasts because lymph oblast look like all of the other immature blood cells that look exactly the same and it's not like they're carrying around a sign saying hey I'm a lymphoblast right or are they well they kind of are because remember we said that all info blasts have this protein inside their nucleus called T DT T DT and only the lymphoblasts have this so none of the other blood cells have it and not even the immature lymphocytes have it so it kind of is like a sign that they're caring around saying hey I'm a lymphoblast so if the cells in the aspera have T DT inside their nucleus then you can go ahead and diagnose the patient with a ll so moving on since there are two different types of lymphoblasts you think that there would be two different types of a ll and there are there are two different types of a ll the first one is called b-cell b-cell a ll and the second type is called a t-cell a ll and we're first going to talk about the b-cell ll so that to this guy over here and going back to our patient that we did the bone-marrow aspiration on we said that in his aspirate there were lots of lymphoblast but how do we tell if that's a T lymphoblast or B lymphoblast so there are lots of markers that only be lymphoblasts will have and there are other markers that only t lymphoblasts will have so certainly you could use those markers to tell them apart but there's another really nifty feature of B cell ALS that you could use to tell them apart and that is that B cell a LLS are associated with translocations so chromosome translocations so I know that there are lots of different leukemias that have translocations associated with them right but a B cell a ll has two very specific translocations associated with it the first is a TT for translocation T 12 21 translocation and all that means is that chromosome 12 and chromosome 21 each have a segment that shifted on to the other chromosome and the second type is a t9 22 translocation and the first and the T 12 21 is usually found in kids who have B cell a ll and the T 922 is usually found in adults who have B cell ll so these translocations are really helpful as super helpful they first they help us diagnose the disease and secondly they help us determine the prognosis of the disease and I say that because it turns out that the T 12 21 translocation is associated with a better prognosis and that's because the leukemia cells that have this translocation inside them the cells themselves are more responsive to treatment to chemotherapy and that's for a whole bunch of scientific reasons but the way I like to think of it is is that 12 and 21 are mirror images of each other so I like to think I like to imagine that there's a mirror in between them and and this is my really poor attempt at drawing a pistol a gun and the gun is shooting therapy chemotherapy at the mirror so that leads to this explosion that kills lots of cells around it and I know it's a really silly way of thinking of it but for some reason I haven't been able to forget that 1221 means better response to therapy and sometimes a bad analogy is more memorable than a good analogy okay so that's b-cell áall now the other type of acute lymphoblastic leukemia is a t-cell áall so now we're talking about this guy over here and I want to start by asking you when the bone marrow releases T cells into the circulation into the blood where do the T cells go well usually they go right into the thymus and they go there so that they can develop a little bit more so in T cell ll you have lots of T lymphoblasts in the blood and they can also go to the thymus and if they do your thymus will get bigger and it'll feel like there's mass mass inside your thymus and that's a problem because if your thymus is growing larger it can compress the structures around it so it can compress the airway and it can compress the esophagus and that'll lead to a whole slew of symptoms on its own so you can get a thymic mass and the other thing that's important is that T cell al ELLs are most often seen in teenagers and something that might help you remember these three things is remembering the letter T so T cell ALS associated with thymic mass and found in teenagers okay so those are acute lymphoblastic leukemias now let's move on to our acute myeloid leukemias so that means in this diagram we're looking at these guys over here get the acute acute myeloid leukemias myeloid leukemias and because there are many types of myeloid cells you you can have several different types of acute myeloid leukemias then acute myeloid leukemias abbreviated a ml so for example you could have an acute myeloid leukemia developing from a myeloblasts so this cell over here and that would give you and that would be called an acute myeloma low blastic leukemia you could also have an AML that develops from a mono blast and that would give you an A cute mono blastic blastic leukemia and in the same way you could have an AML developing from a mega carrier blast and that would give you an acute mega carry me go carry Oh plastic leukemia and you could actually get a leukemia an acute myeloid leukemia developing from an erisa blast but that's so extremely rare that you won't really hear people talk about it doesn't really happen in the real world but it's good to know that it's possible theoretically right so these are so those are all of the different types of acute leukemias now we're ready to talk about the chronic leukemias