UMass Amherst MICROBIO 160 - L20 Risk Factors for Skin Cancer (28 pages)

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L20 Risk Factors for Skin Cancer



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L20 Risk Factors for Skin Cancer

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Pages:
28
School:
University of Massachusetts Amherst
Course:
Microbio 160 - Biology of Cancer and AIDS
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Risk Factors for Skin Cancer Skin Cancer qEach Year over 1 0 million people in the United States find out that they have skin cancer qEstimated new cases and deaths from melanoma in the United States in 2010 New cases 68 130 Deaths 8 700 qNon Melanoma New cases more than 1 000 000 Deaths less than 1 000 What are risk factors for skin cancer qHeredity people with a family history of skin cancer are generally at a higher risk of developing the disease People with fair skin and a northern European heritage appear to be most susceptible qEnvironment level of UV light today is higher than it was 50 or 100 years ago Ozone serves as a filter to screen out and reduce the amount of UV light that we are exposed to With less atmospheric ozone a higher level of UV light reaches the earth s surface qMultiple nevi moles or atypical nevi qOccupational exposure to coal tar pitch creosote arsenic compounds or radium qElevation UV is stronger as elevation increases because the thinner atmosphere at higher altitudes cannot filter UV as effectively as it does at sea level qLatitude the rays of the sun are strongest near the equator qCloud cover places with regular cloud cover may actually reduce UV resulting in a 50 percent lower level of UV light Skin Cancer Risk Factors Tanning beds as bad as tobacco Skin Cancer and Exposure to Sunlight The Electromagnetic Spectrum UVA with wavelength 315 400 nm UVB with wavelength 280 315 nm UVC with wavelength 100 280 nm What to look out for Effects of UV Radiation qUVB is the main cause of skin cancer also 1000 times more effective in causing sunburn qDamages DNA qOxidize lipids and produces harmful free radicals qCauses inflammation which also produces free radicals particularly nitrogen radicals qDisrupts cell communication and causes expression of stress response genes qWeakens the immune responses of the skin Origin of The Three Types of Skin Cancer Incidence and Mortality Rates for Different Types of Skin Cancer From L J Kleinsmith Principles of Cancer Biology Copyright c 2006 Pearson Benjamin Cummings Non Melanoma cancers qNon Melanoma 2 major types usually non Invasive nonmetastatic v 1 Basal Cell Carcinoma 80 v 2 Squamous cell carcinoma 16 Basal and Squamous Cell Carcinomas q Appears as a scaly reddish dome shaped fleshy nodule from 5 mm to few cm if left untreated in size often with a central ulcer q Mostly appears on sun exposed areas of the skin or lips q Pearl like greyish nodule few mm in size appears mostly on the sun exposed areas of the face including the lips scalp neck upper area of the chest or back or on the back side of forearms or hands q Several nodules may merge together A nodule may ulcerate crust over or ooze fluid Melanoma qMelanomas arise from melanocytes and are more dangerous metastasize before tumor is noticed qMelanomas account for only 4 of skin cancers but are responsible for the majority of fatalities Stages of Melanoma Characteristics of Melanoma qMelanomas can develop anywhere on your body qMost often develop in areas that have had exposure to the sun such as your back legs arms and face qMelanoma can occur in areas that don t receive much sun exposure such as the soles of your feet palms of your hands and on fingernail beds Melanoma of the Eye Iris Melanoma If untreated can q Press on the lens to cause cataract and q Invade the angle to cause glaucoma q Most often present in adults Choroidal Melanoma q Rare 6 cases per million people per year in the United States q Most often presents in patients over age 45 with an average age of presentation at 55 Sun Protection Factor SPF qMeasure of a sunscreen s ability to prevent UVB from damaging the skin qSunscreens should be applied 30mins before sun exposure qReapply if you stay out in the sun 2h after you swim or sweat qA wet T shirt offers much less UV protection than a dry one Skin Type Dictates SPF Use q Type I very fair have pale skin burn very easily and rarely tan They generally have light colored hair or red hair and freckles q Type II fair usually burn but may gradually tan q Type III light burn with long exposure to the sun but generally tan quite easily Olive skin q Type IV medium burn with very lengthy exposures but always tan easily as well They usually have brown eyes and dark hair q Type V dark have a naturally brown skin with brown eyes and dark hair Burn only with excessive exposure to the q Type VI dark black skin with dark brown eyes and black hair Burn only with extreme exposure to the sun Distinguishing benign moles from melanoma The ABCD Rule Treating Skin Cancer qChemotherapy If squamous cell carcinoma spreads beyond the skin to the lymph nodes or to other organs systemic affects entire body chemotherapy may be used to kill the cancer cells qRadiation therapy may be used to treat an older adult who has a large tumor tumors that cover a large area or a tumor that is difficult to surgically remove because of location such as one on an eyelid nose or ear BioVex Vaccine for Advanced Melanoma OncoVEXGM CSF Amgen buys BioVex renames T Vec T Vec is a genetically engineered herpes virus an oncolytic herpes virus Two genes were removed one that shuts down an individual cell s defense another that helps the virus evade the immune system a gene for human granulocyte macrophage colony stimulating factor GM CSF was added T Vec is delivered locally by injecting it directly into melanoma lesions The FDA has approved the first in class oncolytic T VEC based on results from the phase III OPTiM study for the local treatment of unresectable cutaneous subcutaneous and nodal lesions in patients with melanoma recurrent after initial surgery OPTiM randomized 436 patients with unresected stage IIIB C and IV melanoma in a 2 1 ratio to receive intralesional T VEC n 295 or subcutaneous GM CSF n 141 T VEC was administered initially at 4 mL x106 PFU mL for 3 weeks followed by 4 mL x108 PFU mL every 2 weeks GM CSF was administered daily at 125 g m2 every 14 days in a 28 day cycle In regards to cancerous tumors the method for assessment used is the Response Evaluation Criteria In Solid Tumors RECIST Partial Response Rate PR A partial decrease of at least 30 of the longest diameter of targeted cancerous lesions sometimes also referring to a 30 decrease in the number of lesions While this indicates that some disease remains in the patient this demonstrates a marked change affected by treatment measures and allows researchers to gauge whether or not further development of the trial


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