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Unformatted text preview: • Cancer biology: tumorigenesis can stem from errors in signaling pathways and cell cycle regulation mechanisms • Cancer is result of uncontrolled cell division o Leading cause of premature death in Canada o In young animal, cell proliferation exceeds cell death o In adult animal there is equilibrium between cell proliferation and cell death loss of equilibrium o Cells are unresponsive to regulation o Caused by mutations in somatic cells • Lung cancer leading cause of death in men and women • Cancer increased in young adults in both sexes • Cancers start o Multi-hit hypothesis A cell needs to undergo multiple genetic mutations in order to push it over the edge to lose cell cycle regulation Older individuals have higher incidence of cancer o Cancer stem cells Either adult SC mutate or somatic cells de-differentiate into SC • Genetic basis for cancer o With either hypothesis the loss of cell regulation that gives rise to cancer is due to genetic mutations —inherited or caused by damage to somatic cells o Two broad classes of genes whose mutations lead to cancer Proto-oncogenes: genes that control he cell cycle and differentiation • Mutations in proto-oncogenes oncogenes = increased activity Tumor suppressors: gene products that actively protect a cell from becoming cancerous • Mutations in anti-oncogenes= loss of restraint Benign tumor Malignant tumor Slow growth, localized Closely resemble normal cells Express normal cell specific markers Does not metastasize Mass effect Divide rapidly High nucleus/cytoplasm ratio Less differentiated than normal cells Loss of cell specific markers Invades surrounding tissues (metastasis) • Metastasis: spread of tumor cells, enter circulatory system o Proliferate & establishment of secondary area of tumor growth o Loss of cell specific markers • Metastatic cells overcome constraints of environment o Extracellular matrix, basal lamina, cell adhesion mechanism to keep normal cells in place o At secondary site, cell multiplies creating a secondary tumor • Integrating cells into tissues o Evolution of multicellular organism (plants and animals) o Specialized cells group together to perform a specific task Formation of tissues • Ex. muscles contract, xylem tissues transport water Formation of organs • Perform one or more functions • Ex. heart muscles, valves and blood vessels work together to pump blood through body o Coordinated functioning of many types of cells within many different tissues=successful survival • Movement, metabolism, reproduce, etc. • 100s of different cell types in vertebrates o Diverse form and function o Can be classified into 5 main classes of tissues Epithelial Connective Muscular Nervous Blood o The whole being greater than the sum of its parts • Cell adhesion- stable interactions • Assembly of distinct tissues and organization into organs determined by molecular interactions at cellular level o Direct cell-cell adhesion involves CAM...
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This note was uploaded on 04/04/2012 for the course CELL BIO 2b03 taught by Professor Leenapatel during the Spring '11 term at McMaster University.
- Spring '11