MICROBIO 160 1st Edition Lecture 16 Outline of Last Lecture I. Skin Cancer Cases and Deaths II. Risk FactorsIII. Tanning BedsIV. Skin Cancer and Exposure to SunlightV. Types of UV RadiationVI. How UV damage leads to CancerVII. Types of Skin CancerVIII. Stages of MelanomaIX. Treating Skin Cancer X. BioVex Vaccine for Advanced MelanomaOutline of Current Lecture I. Cervical Cancer HistoryII. HPV TypesIII. How does HPV cause CancerIV. Risk FactorsV. Prevalence of HPV InfectionVI. Pap test VII. Colposcopy and Cervical ExamVIII. Treating Cervical CancerIX. Advanced StagesX. HPV Vaccines and CancerThese 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.Current LectureCervical Cancer History:- Epidemiologists working in the early 20th century noted the following:o Cervical cancer was common in female sex workers o It was rare in nuns, except for those who had been sexually active before entering the convento It was more common in the second wives of men whose first wives had died from cervical cancer (infectious agent) About 20 years ago, cervical cancer was linked to human papilloma virus infection Now, over 100 strains of HPV are known HPV Types: - 100 types of HPV; 23 are present in the genital tract- 12 main types associated with cancer and considered “high-risk” o 16 and 18 (most common), 31, 33, 35, 39, 45, 51, 52, 56, 68, 69- Most women will clear an HPV infection within 9-15 months- Women with persistent, high-risk HPV infection are 300x more likely to develop cervicalcancerHow does HPV causecancer?Risk Factors of CervicalCancer:- HPV infection- Multiple sex partners- Started having sex before age 18- Other STI’s (HIV, syphilis, Chlamydia)- Smoking- Multiple pregnancies- Oral contraceptivesHPV gene expression timing:- Viruses express their genes in 2 phases—early (E) and late (L)The HPV early genes E6 and E7 are associated with cancer:- E6 protein cause p53 tumor suppressor degradation and promotes telomerase activity- E7 protein causes Rb tumor suppressor degradationHPV hides from the immune system by inserting into host DNA= persistent infection- Diet- Family history- Low socioeconomic status- Molecular genetic factors: p53, RbPrevalence of HPV Infection:- Currently, there are around 20 million people infected with the various types of HPV in the US alone- Approximately 6.2 million new cases of HPV infection occurring annually- Between 75% and 80% of sexually active individuals will become infected with HPV within their lifetime- Each year, more than 20,000 HPV-associated cancers occur in women; cervical cancer is the most common- About 12,000 HPV-associated cancers occur each year in men; oropharyngeal cancers arethe most commonPap Test and Cervical Cancer: gold standard for trying to detect cervical standard- The pap test was developed in 1943 by Dr. George Papanicolaou—since then, early detection of cervical cancer has greatly improved- As a result, cervical cancer dropped from the second-leading cause of cancer deaths among American women to the 13th in the US- This is the most successful screening test, reducing cervical cancer mortality by 70% in the US- New guidelines suggest that women should have their first Pap smear by the age of 21 or within 3 years of first sexual intercoursePap Smear Morphology:- Once the test was discovered and they started implementing it- Invasive cervical cancer dropped in women- The test tells when the cells look slightlyabnormal- Dysplasia: a higher nuclear to cytoplasmic ratio—this means the nucleus is larger than it should be for the size of the cell- Mild dysplasia: the nucleus is about 3-4 times larger than it should be - Moderate dysplasia: the nucleus is 5-6 times larger than it should be- Severe dysplasia: the nucleus is taking up most of the cell Colposcopy and Cervical Exam: camera that helps doctors look to see inside the cervix- Once the doctor is visualizing it, the doctors use a brush to try to scrape off cells to check for disease or other problems under a microscope- Cervical biopsy “punch”: small tissue samples are taken from the cervix and examined for disease or other problemso Normal cervix: smooth, normal tissueo Low grade CIN: a little roughed upo High-grade CIN: more roughed upo Cancer: lumps or bumps on the cervixProgression of Cervical Cancer: how much of the tissue is covered with roughed-up—gives you an idea of how far the cancer has actually gone Treating Cervical Cancer: early stages- Traditional radiation and Chemotherapy- LEEP: Loop Electrosurgical Excision Procedure—hot wire that cuts right through the tissue—coagulates the tissue at the same time so there is little to no bleeding - Cone of tissue can be removed: carve out a channel to remove all of the tissue—sent to a pathologist - Cryo probe: they can freeze the tissue which leads to the destruction of the abnormal cervical tissue Advanced stages:- (For stage IIB) Hysterectomy: removes the uterus and may also remove the cervix (total) an the vagina (Radical)- Recurrent: (For stage IVA or IVB) pelvic externeration o Since the bladder and rectum are removed, the surgeon will utilize a segment of the intestine to form a new bladder that can be drained with a catheter, and he willfix what is left of the large intestine to the wall of the abdomen so that waste matter can pass through an opening in the abdomen and into a special bagHPV also causes Oral and Throat Cancer: a virus contracted through oral sex is the cause of some throat cancers- In Men, Oral sex may cause more throat cancer than smokingo A 20 year study of throat tumors found that the percentage of oral cancer linked toHPV surged from 16-72%o By 2020 it is estimated that throat cancer from HPV will become more common than HPV-caused cervical cancer HPV Vaccines and Cancer: - Given as 3 shots to protect against HPV infection and HPV-related diseases- Two vaccines (Cervarix and Gardasil) have been shown to protect against most cervical cancers in women- Gardasil also protects against genital warts and has been shown to protect against cancersof the anus, vagina, and vulvao Both vaccines are available for females - HPV vaccines offer the greatest health benefits to individuals who receive all three doses before having any type of sexual activityo That’s why HPV vaccination
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