Human papillomavirus and cervical cancer: mechanisms of carcinogenesis, epidemiology, diagnostics and prophylaxis

Infekcija humanim papiloma virusom (HPV) najčešća je spolno prenosiva bolest i pretpostavlja se da genitalnu infekciju ovim virusom ti jekom života stekne 75 – 80 % spolno aktivnih žena i muškaraca. Od ranih osamdeseti h kada je Harald zur Hausen (dobitnik Nobelove nagrade za fiziologiju ili medicinu 2008. godine) dokazao humani papiloma virus (HPV) genotipa 16 i 18 u karcinomu cerviksa, u velikom broju studija potvrđeno je i znanstvenim činjenicama dokazano da je infekcija HPV-om ključni čimbenik u razvoju karcinoma cerviksa. Maligne promjene cerviksa nastaju ako su ispunjeni višestruki uvjeti koji su defi nirani virusnim značajkama, staničnim protuvirusnim mehanizmima i imunim odgovorom domaćina. Virusnu komponentu čine genoti p virusa, perzistencija i intenzitet infekcije, a imunogenetička konstitucija pojedinca, stanično posredovani imuni odgovor i utjecaj vanjskih čimbenika kao što su lijekovi i bolesti, definiraju imunopatogenetski doprinos domaćina. Ključni proteini uključeni u nastanak karcinoma cerviksa su virusni onkogeni, E6 i E7, koji interferiraju s nizom staničnih procesa te dovode do nekontrolirane proliferacije i stanične imortalizacije, stoga je značaj molekularnih studija koje se bave problematikom HPV-a upravo u boljem razumijevanju patogeneze HPV-a te primjeni stečenih spoznaja u prevenciji virusne infekcije, razvoju profilaktičkog cjepiva i uvođenju molekularne dijagnosti ke kao standarda u procjeni rizika za žene izložene kroničnoj infekciji HPV-om.Human papillomavirus (HPV) infecti on is esti mated to be the most common sexually transmitt ed disease and about 75-80% of sexually active men and women will be infected with HPV at some point in their lifeti me. Since the early 1980s when Harald zur Hausen (winner of the Nobel Prize in 2008 for Physiology or Medicine) detected the HPV genotypes 16 and 18 in cervical cancer, a large number of studies have provided scienti fi c evidence that HPV infection is a key factor in the development of cervical carcinoma. Malignant changes of the cervix occur if multiple conditions are met and they are defined by virus characteristics, anti viral mechanisms and by the cellular immune response of the host. Viral components important in carcinogenesis are viral genotype, intensity and persistence of the infecti on, while immunogenetic constitution of the individual, cell mediated immune responses and influence of the external factors such as drugs and diseases defi ne immunopathogenetic contributi on of the host. Key proteins involved in the development of cervical cancer are viral oncogenes, E6 and E7, which interfere with a variety of cellular processes and lead to uncontrolled cell proliferati on and immortalisation. Therefore, the importance of molecular studies dealing with HPV lies in the fact that they enable us to better understand the HPV pathogenesis and facilitate application of the acquired knowledge in the preventi on of HPV infections, development of prophylactic vaccines and introducti on of molecular diagnosti cs as a standard in the risk assessment for women exposed to the chronic HPV infection

MOLECULAR DIAGNOSIS OF HEPATITIS C INFECTION

SAŽETAK Svjetska zdravstvena organizacija (WHO) prepoznala je hepatitis C kao svjetski problem. Na osnovi procjena iz godine 1999., 170 milijuna ljudi bilo je kronično inficirano hepatitis C virusom (HCV). HCV vodeći je čimbenik neizlječivih oboljenja jetre, uključujući karcinom jetre. Za otkriće HCV-a godine 1989., zaslužni su molekularno-biološki postupci na kojima se zasniva suvremena dijagnostika hepatitisa C. Dijagnostički testovi dijele se na serološke testove kojima se dokazuju anti-HCV protutijela, te na molekularne testove kojima se u inficirane osobe dokazuje, određuje i obilježuje HCV-RNA genom. Kvalitativni molekularni testovi primjenjuju se za potvrđivanje infekcije, te u kontroli darivane krvi. Praćenjem broja virusnih kopija, kvantitativni HCV-RNA testovi daju podatke o odgovoru na antivirusnu terapiju. HCV jest heterogeni virus koji se na osnovi genomske promjenljivosti svrstava u 6 osnovnih genotipova, te u više podtipova. HCV genotipizacija bitna je za kliničara, budući da se prema pojedinome genotipu može procijeniti odgovor na antivirusnu terapiju, a određivanjem HCV genotipa odabire se optimalni terapijski postupak vezan uz duljinu razdoblja terapije i dozu ribavirina.ABSTRACT The World Health Organization recognized hepatitis C (HCV) as a global health problem estimated that in 1999, over 170 million people were chronically infected with HCV. HCV is leading cause of end-stage liver disease and hepatocellular carcinoma. The discovery of hepatitis C virus (HCV) in 1989 using molecular biology methods has led to the rapid evolution of the field of HCV diagnostics. Diagnostic tests for HCV can be divided into serological assays that detect antibody to HCV and molecular assays that detect, quantify and characterize HCV-RNA genome within infected patient. Qualitative molecular nucleic acid tests are used for confirmation of HCV infection and for screening blood donation. Quantitative HCV-RNA tests provide prognostic information for monitoring the response to antiviral therapy. HCV is heterogeneous virus with six distinct genotypes and numerous subtypes. HCV genotype tests are important clinically because they predict most accurately the chance of antiviral response and are routinely used for selecting treatment regimens regarding the duration of interferon therapy and ribavirin dosage

Distribution of Human Papillomavirus Types in Different Histological Subtypes of Cervical Adenocarcinoma

Little information is available regarding distribution of HPV types in different histological subtypes of adenocarcinoma (AC). Thus, in this study we examined the frequency of high-risk (hr) HPV types in AC, adenocarcinoma in situ (AIS) and adenosquamous carcinoma (ADSQ). A total of 102 cases of primary cervical adenocarcinoma (26 AIS and 76 invasive AC) obtained from pathology files from 1995–2006 were histologically subtyped. Our results demonstrated that endocervical type occupied the major subtype of AC (22/66) followed by ADSQ (17/66) where as in the group of AIS endocervical type (12/23) was followed by intestinal type of AIS (7/23). Successful DNA extraction was obtained in 89 samples; 81 out of 89 (91.0%) tested positive for HPV DNA. The prevalence of HPV DNA in AIS, AC and ADSQ was 91.3% (21/23), 90.9% (60/66) and 94.1% (16/17), respectively. We found HPV 18 type to be the most predominant type in AIS (11/21) and AC (17/60) followed by HPV of undeternmined type in AIS (3/21) and HPV 16 in AC (9/60) as the sole viral type. HPV 18 was most frequently detected type in all histological subtypes of AIS and AC. We have detected HPV DNA in all 5 samples of clear cell carcinoma (CCC), although other studies have reported a highly variable prevalence of HPV DNA in CCC. The most prevalent HPV type in ADSQ was HPV-16 followed by HPV 33 as single type. The observed overall predominance of HPV 18 in AIS ( 2= 6.109, p£ 0.025) and AC ( 2 = 8.927, p£0.01) as well as of HPV 16 in ADSQ ( 2 = 10.164, p £ 0.01) was statistically significant. Our data revealed statistically significant predominance of single hrHPV infections in AIS (16/21; 2 = 11.523, p £ 0.001) and AC (37/60; 2 = 6.533, p £ 0.025) whereas multiple hrHPV infections were more abundant in AC comparing to AIS (23/81and 5/81, respectively; 2 = 13.989, p £ 0.001)

Prevalence of Human Papillomavirus among Croatian Women Attending Regular Gynecological Visit

Human papillomavirus (HPV) infection has been identified as major risk factor for cervical intraepithelial neoplasia (CIN) and invasive cervical cancer. About 40 HPV viral types are commonly found in the genital tract. Most HPV infections resolve spontaneously, while persistent infection with oncogenic types, namely HPV 16 and 18 is necessary for CIN to occur and progress to cancer. Cervical screening is presently based on the Pap smear that is designed to diagnose precancerous lesions and cervical cancer. The aim of this study was to investigate the prevalence of HPV DNA and to determine HPV types distribution among 361 women attending regular gynecological visit. There were 205 women (29±8 years old) without determined abnormal cervical lesions and 156 women (34±15 years old) with abnormal Pap smear; low grade squamous intraepitehelial lesions (LSIL, n=69), high grade squamous intraepithelial lesions (HSIL, n=72) and atypical squamous cells of undetermined significance (ASCUS, n=15). HPV DNA detection and genotyping was performed by Hybrid Capture 2 assay and additionally by consensus and type-specific primers directed PCR. The overall prevalence of high-risk HPV (hrHPV) in women with abnormal Pap smears was 67.9% (106/156), of which in ASCUS 33.4% (5/15), LSIL 62.3% (43/69) and HSIL 80.6% (58/72). In HPV positive specimens, HPV 16 was found as predominant type in 60.4% cases, followed by HPV 31 (8.5%), HPV 33 (6.6%) and HPV 18 (3.7%). In the group of women without obvious cervical changes the overall hrHPV prevalence was 35.6% with HPV 16 found in 43.8% cases, followed by HPV 31 (17.8%), HPV 33 (9.5%) and HPV 18 (6.8%). In both study groups, women with and without cervical lesions, the prevalence of HPV of indeterminate type was 14.2% and 13.7%, respectively. Our results indicate that cervical intraepithelial lesions are largely associated with HPV type 16, followed by HPV types 31, 33, 18 and HPV of indeterminate type. Although there is a significant difference in hrHPV DNA prevalence among two groups, no significant differences between particular hrHPV types distribution were observed

Expression of Cell Cycle and Apoptosis Regulatory Proteins and Telomerase in Melanocitic Lesions

To gain insight into the role and association of cell cycle and apoptosis regulatory proteins and telomerase activity in the course of progression of melanocitic lesions we have examined immunohistochemicaly, expression and the distribution of p53, bcl-2, Ki-67 and telomerase in 25 samples of common and dysplastic nevi, and 45 samples of primary invasive melanomas. Protein p53 expression was significantly increased in dysplastic as compared with common nevi and melanomas (p<0.001). Bcl-2 protein expression was significantly increased in melanomas as compared with common aquired and dysplastic nevi (p=0.001). Nevi and melanomas exhibited clear-cut differences in terms of Ki-67 expression. Telomerase expression was significantly increased in melanomas as compared with common acquired (p=0.014) and dysplastic nevi (p<0.001). Enhanced telomerase activity in association with increased bcl-2 expression in the course of melanoma progression could contribute to development and progression of melanoma

Postinfectious Glomerulonephritis and Epstein-Barr Virus Co-Infection

Contrary to group A b-hemolytic streptococcus as the most common cause of postinfectious glomerulonephritis (PIGN), Epstein-Barr virus (EBV) is only occasionally associated with acute renal involvement. We describe an 11-year-old boy who presented with clinical signs of infective mononucleosis and acute glomerulonephritis characterized by edema, hypertension and dark colored urine with diminished renal function. Serology tests confirmed streptococcal infection and acute EBV infection. Persistently depressed C3 complement and gross hematuria indicated renal biopsy which shows PIGN-type picture and, in addition, acute interstitial nephritis, both conclusive of streptococcal infection. We performed tissue DNA extraction by polymerase chain reaction (PCR) and demonstrated EBV-DNA from the kidney specimen supporting EBV involvement in renal tissue. This is the first reported case of PIGN with serologically-proven streptococcal and simultaneously, acute EBV co-infection. EBV-DNA extraction supported the EBV involvement in renal tissue suggesting that both etiologic agents might have contributed to renal inflammation. Adding serology evaluation for EBV in cases with typical clinical signs of infective mononucleosis and renal symptoms, EBV might be more commonly associated with PIGN than is currently appreciated