BIOL 3510 1st Edition Lecture 26 Outline of Last Lecture I Tissues II Tight Junctions III Cell Junctions IV Three Key Mechanisms V Embryonic Stem Cells Outline of Current Lecture I Properties of Cancer Cells II Genetic Instability Factors III Causes of Cancer IV Treating Cancer Current Lecture Cancer when rouge cells start ignoring the rules Two properties of cancer cells 1 Divide when they are not supposed to 2 Move to and proliferate in tissues where they do not belong metastasize Benign tumor cells only have the first property while malignant have both A variety of factors can contribute to genetic instability Defects in DNA replication Defects in DNA repair Defects in cell cycle checkpoint mechanisms Mistakes in mitosis Abnormal chromosome numbers Causes of Cancer 1 Accumulation of mutations o Every gene in your body has been mutated more than 10 9 times o Mutations lead to genetic instability which raises the mutation rate These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o Environmental factors that promote cancer carcinogens tobacco smoke ionizing radiation UV light etc 2 Viruses o Example human papiloma virus causes cervical cancer Cancer is a disease of old age Mutation in cancer cells give them an advantage over normal cells Cervical cancer tumor progression Properties of Cancer Cells 1 2 3 4 5 6 7 Reduced dependence on signals from surrounding cells i e abnormal Ras activity Less prone to apoptosis ie loss of p53 Proliferate indefinitely ie telomerase reactivated Genetically unstable increased mutation rate abnormal chromosome number Abnormally invasive ie loss of cadherins Abnormal metabolism Able to survive in foreign tissues Mutated genes involved in cancer are called oncogenes or tumor suppressor genes Conversion of a proto oncogene into an oncogene Retinoblastoma cancer of the retina Colorectal cancer arises from the epithelial lining of the colon and rectum Most cases no hereditary component Small hereditary component cancer is foreshadowed by development of 100s of polyps Colorectal cancer is linked to mutations in adenomaatous polyposis coli ApC and beta catenin Cells in polyps accumulate more mutations leading to cancer Cancer is usually not detected until a tumor has 100s of millions of genetically diverse cells Treating Cancer 1 Surgery 2 Radiation and DNA damaging chemotherapy o Normal cells fix the damage or undergo apoptosis o Cancer cells continue dividing and pass along broken chromosomes leading to cell death 3 Drugs that target specific cancers o Gleevec treats chronic myeloid leukemia 4 Drugs that block blood vessel formation 5 Using the immune system Gleevec treats chronic myeloid leukemia by blocking the action of the oncogenic kinase Abl
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