WHAT IS CANCER Origin of Word Cancer First coined in the 15th Century by Hypocrites means crab used to describe a bunch of diseases that choke out the body WE COULD THINK OF CANCER AS An ERROR in GENETIC replication Mitosis GOES ALL WRONG UNCONTROLLED CELL REPLICATION APOPTOSIS Apoptosis is a type of cell suicide which is programmed and involves a series of cellular events It occurs in cells that are recognized as abnormal What is Cancer l growth and old cell death are kept in balance In cancer this balance is disrupted This disruption can result from uncontrolled cell growth or loss of a cell s ability to undergo cell su Benign Proliferate without metastasis Only dangerous if they interfere with adjacent tissue function Malignant Cancer Invasive tumors of any part of the body Spread via blood or lymph Neoplasm A Stickiness Problem You Mean Like Tape or Glue In cancer cells the cell membrane glycoproteins are modified so the cells come loose and travel These cells can adhere to other tissues of the body where their surface receptors find a match for adhesion What Is Cancer Uncontrolled cell growth Benign cells similar to the surrounding tissue enclosed in a membrane non spreading Malignant capable of invading surrounding structures Metastasis spreading of cancer cells they don t stick to each other very well either through blood or lymph The Role of DNA Human cells have 23 sets of chromosomes Chromosomes contain genes code for proteins Cells reproduce by dividing in two Mutations mistakes in the DNA Base change change from one base to another Base insertion deletion add subtract a base Mutations and Cancer Cancer caused by a mutation that deregulates the cell cycle Allows cells to divide when not necessary Some mutations keep cells from dying when they are scheduled to Progression of a Neoplasm Hyperplasia Excessive Growth of Cells usually one mutation suffered Dysplasia Abnormal Growth of Cells new mutation Carcinoma in Situ A Cancer Growth That remains in place additional mutation Metastasis Cancerous Growth Gains Ability to Spread Characteristics of Cancer Cells IMMORTAL Rather than terminating after 50 or 60 divisions like normal cells they keep dividing Example Hela Cells in tissue culture 50 years and still dividing LACK CONTACT INHIBITION Normal cells stop dividing when they become overcrowding because mitosis is inhibited when cells come in contact with others This is called contact inhibition Tumor cells have lost ability to sense proper cues and continue to divide forming a mass or tumor UNSPECIALIZED Normal cells will start to differentiate into specialized cells such as muscle for contraction Tumor cells remain unspecialized Very PENETRATING Ability to Penetrate the Basal Lamina a tissue located just beneath dividing cell layer REDUCED GROWTH FACTOR REQUIREMENTGrowth factors are chemicals that stimulate cell division Tumor cell can divide without them or very little of them ANGIOGENESIS Tumor cells require addition food and oxygen They actually release growth factors that induce a branching network of blood vessels into the cancerous tissue ABILITY TO INVADE Normal cells cling to others cancer cells do not This allows for cancer cell to be transported via the circulatory or lymphatic system during metastasis ONCOGENES Proto oncogenes These are normal genes which play a role is cell growth and division Oncogene A gene that causes cancer You can inherit an oncogene OR have a proto oncogene that mutates into an oncogene They have the potential to become oncogenes under certain conditions such as a point mutation or a translocation P53 Damage One of the many Carcinogens in Tobacco Smoke known to damage the p53 gene is called benzo a pyrene Researchers believe that mutational damage carcinogenesis in either the p53 gene or its protein product is involved in 50 60 of all cancers Structure of DNA Gene A functional Definition On a chromosome a smaller series of the nucleotide bases along the DNA spiral that constitute a code that can be ultimately expressed into a protein FROM GENE TO PROTEIN From Gene To Protein What is a Mutation MULTIPLE MUTATIONS It is important to realize that cancer does not occur with a single mutation At least 3 mutations must occur for a cancer to develop 1 the oncogene must be activated or a protooncogene must be mutated to an oncogene 2 A Tumor suppressor gene must be turned off or mutated same thing 3 The second or back up tumor suppressor gene must be turned off Factors Believed To Cause Cancer Another Type of Mutation Translocation Another Type of Mutation Translocation Multiple Mutations Cancer Malignant Tumors are Classified According to the Types of Cells That Give Rise to Them CARCINOMAS Arise from epithelia tissue that cover body surfaces line internal cavities SARCOMAS Arise from connective and fibrous tissues such as muscle bone cartilage and membranes covering fat LYMPHOMAS Cancers of the lymph nodes lymphatic system B cells and T Cells LEUKEMIAS Cancers of blood forming cells which reside in the bone marrow Other lymphocytes What Causes the Mutations 80 of cancers are environmentally induced From radiation toxins and mutagens pesticides growth hormones Sex Hormones too common industrial chemical waste fuel emissions dioxin asbestos some food additives As the environment becomes more toxic more cancer is evident Cancer Rates Dramatically Increase w AGE Tobacco is Responsible for One Third of All Cancer Deaths Cancer Rates Dramatically Increases with AGE Nobel Prize Awarded To Peyton Rous For Discovering and proving that an infectious agent a virus could cause cancer In 1987 50 years later To Peyton Rous For Discovering and proving that an infectious agent a virus could cause cancer In 1987 50 years later Viruses are small infectious agents that cannot reproduce on their own Instead they insert their nucleic acid into the host DNA Now the living cell host produces viral nucleic acid and new viruses at expense of host In cancer viruses this sort of transformation can cause the host cell to become malignant Naming Oncogenes Some Examples Usually 3 letters long and italicized Letter prefix tells whether cellular or viral src causes Rous sarcoma in chickens ras causes lung colon and bladder cancers c myc causes B cell lymphoma BRCA I this is a tumor suppressor gene which is mutated in some inherited forms of breast cancer Environmental Chemicals known Carcinogens AsbestosAcrylamide Aromatic Benzene Rings Nitratromines Halogenated