MicroBio 160 1st Edition Lecture 13 Outline of Last Lecture I Breast Cancer Staging II Sentinel Lymph Node Biopsy III Sentinel Lymph Node Detection IV Surgery for Breast Cancer V Radiation Therapy vs Brachytherapy VI Hormone Therapy VII Tamoxifen the first SERM VIII Raloxifene an alternative SERM IX How your body makes Estrogen after Menopause Outline of Current Lecture I Facts about Addiction to Nicotine II What s in Cigarettes III IV V Linking Cigarettes to Cancer Mutations of p53 and K ras in Lung Cancer Non small Cell Lung Cancer VI Small Cell Carcinoma VII Renal Cell Carcinoma and Smoking VIII Diagnosis IX Treatments X Exposure to Smoking XI Electronic Cigarettes Current Lecture Facts about Addiction to Nicotine Nicotine is the tobacco plant s natural protection from being eaten by insects Within 8 seconds of first puff nicotine arrives at the brain s reward pathways producing more dopamine telling brains that we are happy so don t quit Once inside the brain nicotine gains direct and indirect control over the flow of more than 200 neurochemicals 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 Men who don t quit smoking lose an average of 13 2 years of life while smoking women lose even more an average of 14 5 years What happens when you smoke Falling blood nicotine levels Brain generates craving Inhale new nicotine Brain releases dopamine What is in cigarettes Cigarette Tar it is the sticky brown substance which causes yellow brown stains on fingers teeth clothes and furniture The more you smoke carcinogens get into lungs and they will have effects on your DNA and immune system if they are no longer protecting us we are at higher risks Tar is a mixture of substances that together form a sticky mass in the lungs Tar in cigarettes also paralyzes the cilia the small hairs which protect and clean the lungs The last puff can contain more than twice as much tar as the first puff As you can see the graph shows that as tar concentration increases the amount of DNA damage in rat thymocytes increases As we have discussed previously damage to your DNA can increase your risk of cancer Linking Cigarettes to Cancer 1 Burning tars in cigarettes create the chemical benzo a pyrene BP which is absorbed by lung tissue 2 Within the cell s nucleus BP is modified to BPDE and binds to the tumor suppressing gene p53 3 Benzopyrene BP causes mutations at three specific hot spots on the p53 gene which results in unrestricted cell division cancer Mutations of p53 and K ras in Lung Cancer P53 Mutations in the p53 gene are found in 70 of lung tumors the highest rate for any cancer The p53 protein is a tumor suppressor analogous to car brakes because its activity helps counter tumor development o P53 occupies a checkpoint in the cycle of cell division where it senses DNA damage or mutations o The cell cycle is composed of 4 stages P53 works at 2 cell cycle checkpoints P53 detects DNA damage and signals the cell to stop dividing allowing time for a mutation to be repaired before it is passed on to daughter cells It is also the primary protein that starts apoptosis K ras it s an oncogene that needs to receive a growth factor in order to send signals accelerator The protein produced by the K ras gene is a tumor activator K ras is analogous to a car accelerator because its overactivity contributes to tumor development The K ras protein resides on the inner side of the cell membrane where it conducts growth signals from cell surface receptors to the nucleus signal transduction o Mutations K ras gene result in a K ras protein that is essentially stuck in an on position signaling cascade in the absence of any signal from a growth factor Non small Cell Lung Cancer 3 types Adenocarcinoma cancer originating in the lung gland o Usually develops on the outer boundaries of the lungs and is more commonly found in women than in men o Cause 40 of lung cancers in the US Squamous cell carcinoma thin flat layer of cells like the skin organs and tissues o Commonly starts in the bronchi and may not spread as rapidly as other lung cancers 30 Large cell carcinoma the cells are larger than normal cells o Causes 15 of all lung cancer in US Small Cell Carcinoma aka oat cell carcinoma more deadly when the cell is smaller than normal cells and is a very aggressive cancer that often spreads to other parts of the body It can create its own hormones which alters body chemistry Smoking tobacco is the major risk factor for developing small cell lung cancer SCC of the lung has the most aggressive clinical course of any type of pulmonary tumor with a median survival from diagnosis of only 2 4 months without any treatment o It has a greater tendency to be widely spread by the time of diagnosis which is much more responsive to chemotherapy and irradiation Renal Cell Carcinoma and Smoking renal cell carcinoma is the most common form of kidney cancer Studies show that smokers are twice as likely as nonsmokers to develop this type of kidney cancer In addition to RCC smokers are more likely to develop o Renal failure causes kidneys to shut down life threatening condition o Renal sarcomas rare and attack the kidney s connective tissue o Transitional cell carcinomas less common form of kidney cancer found in connecting tubes in the kidneys and bladder Tobacco is a leading cause of this type of cancer Why do you think this is Increases blood pressure and heart rate Reduces blood flow in the kidneys Increases production of angiotensis II hormone produced in kidney Narrows the blood vessels in the kidneys Damages arterioles branches of arteries Forms arteriosclerosis thickening and hardening of the renal arteries Accelerates loss of kidney function Diagnosis There are many ways including chest x ray CT scan MRI lung biopsy sputum cytology positron emission tomography PET bronchoscopy mediastinoscopy bone scan for lung cancer ct scan of the brain for lung cancer thoracentesis for lung cancer o Complications excessive bleeding can occur when taking a biopsy or performing bronchoscopy thoracentesis or mediastinoscopy o Exposure to X rays Treatment Stage 1A Good prognosis 49 75 o Stage IA tumor 3cm or less Stage 1B 45 55 o Stage IB tumor more than 3cm but less than 5cm Stage IIA 30 50 o Stage IIA tumor is 5cm or less it has spread to the main bronchus and pr spread to lymph nodes OR the cancer is larger than 5cm but less than 7cm and has not spread
View Full Document
Unlocking...