Cancer epigenetics

Published on July 31, 2023   30 min

Other Talks in the Series: The Molecular Basis of Cancer

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Hello. My name is Andres Blanco. I'm an assistant professor at the University of Pennsylvania. Today's lecture is going to be on Cancer Epigenetics. Now before we can understand the cancer part, we need to understand the epigenetics part.
So what is epigenetics? Well, we all know genetics is the study of heredity and the variation of inherited characteristics,
so what about epigenetics? Well, let me start with few examples. Let's look at these plants here. You'd think that these are different strains of plants, but they're actually identical. They have these different petal shapes, but the offspring of these plants will look like this one and the offspring of these plants will look like this one, and then let's look at these mice here. These are also all genetically identical despite the fact that you probably think they come from different strains. The offspring have the same coat color that the parents have and then let's think about these cells here. Different cell types of the mammalian organism, they're also very different in functionality and in appearance, but of course if it came from the same individual they are genetically identical, so what's going on here? In the case of the plants, a gene that's controlling the petal shape, it's actually silenced by a modification of DNA called DNA methylation. In the case of the mice, a gene that's controlling the coat color is set in the on-state or the off-state depending on whether a retrovirus which is inserted into the genome is right near that gene is itself in on or an off state and that state is heritable over generations and then looking at the different cell types we know that they all start from one cell the zygote, but over development the cells mature into very different cell types expressing very different gene expression programs and these gene expression programs are quite stable. Once these identities are acquired as mature cell types they tend not to change, so these are a few examples of epigenetics. Now, there's no one accepted definition of epigenetics, but for the purposes of the talk we can use this. We could think of epigenetics as a study of heritable phenotypic changes not involving alterations in the DNA sequence.