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Unformatted text preview: Lecture #12 – Thursday, 5/8/08- 1 - Announcements: - Midterm . The mean score was 75%. If you’re interested in your score, you can email me (Tiffany, [email protected] ) for your scores. If you have additional questions about your scores, email the professor ( [email protected] ). o We’ll hand it back Tuesday (next lecture). DNA Repair and Cancer Figure 11.9: How changes can occur in cancer- LOH (Loss of Heterozygosity) is associated with the movement of epithelium from normal hyperplastic adenoma (benign) carcinoma metastasis. - LOH just the loss of one copy of the allele/loss of one of the two chromosomes or regions of the chromosomes that contains one of the other alleles of whatever gene we’re talking about. (We’ve talked about it in the context of tumor suppressor genes). Figure 11.11: Various Pathways of LOH/specific changes that accompany this Various coordinated pathways that can come out of any of these specific LOH at these various chromosomes (like 17 and 5) Figure 11.12: Conceptual framework of continual expansion of cells following mutation. Concept: retaining mutated and continually expanding cells within overall tumor population Figure 11.14a: Cancer Stem Cells - Screening through tumor population for specific cell types that are at the root of maintenance of the tumor and tumor phenotype- They are like cancer stem cells of the hematopoietic system in that they are cells at the root constantly dividing and self-renewing give rise to other cells that go on to make up bulk of tumor Figure 11.14b: Example images of how an isolated cancer stem cell population can take a small fraction of individual tumor cells and induce tumor growth when put back into an animal. Figure 11.15: Brain Tumor grouping of cells- Concept here: There are potentially specific markers or expression levels of certain alleles that can identify these/for certain alleles that are expressed at higher levels on these cancer stem cells. If we can find them and identify them, we can target them with greater efficiency and eliminate tumor growth. Killing stem cells may be the key to eliminating tumor group. They are the more important fraction. Figure 11.16: Definition of a stem cell- Self-renewing cells- Gives rise to transit amplifying cells – able to proliferate but are not themselves stem cells Lecture #12 – Thursday, 5/8/08- 2 -- Gives rise to even more post-mitotic differentiating cells – don’t divide; carry out functions of the tissue.- True of any stem cell in hematopoietic, skin, colon, many proliferating cell types. In epithelium, have stem cells and offshoots that are more differentiated and then ultimately a post mitotic differentiated cell that no longer divides and carries out function of the tissue Figure 11.17: Transformation- If a stem cell is mutated, most of the time, it will continue to make transit amplifying cells that will make up the bulk of the tumor....
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- Spring '08
- cells, cancer stem cells