Detection and typing of human papillomaviruses by polymerase chain reaction in cervical scrapes of Croatian women with abnormal cytology

Presence of high-risk HPVs, EBV, and MMTV in human triple-negative breast cancer

Breast cancer, the most frequent disease amongst women worldwide, accounts for the highest cancer-related mortality rate. Triple-negative breast cancer (TNBC) subtype encompasses ~15% of all breast cancers and lack estrogen, progesterone, and HER2 receptors. Although risk factors for breast cancer are well-known, factors underpinning breast cancer onset and progression remain unknown. Recent studies suggest the plausible role of oncoviruses including human papillomaviruses (HPVs), Epstein-Barr virus (EBV), and mouse mammary tumor virus (MMTV) in breast cancer pathogenesis. However, the role of these oncoviruses in TNBC is still unclear. In the current study, we explored the status of high-risk HPVs, EBV, and MMTV in a well-defined TNBC cohort from Croatia in comparison to 16 normal/non TNBC samples (controls) using polymerase chain reaction assay. We found high-risk HPVs and EBV present in 37/70 (53%) and 25/70 (36%) of the cases, respectively. The most common HPV types are 52, 45, 31, 58 and 68. We found 16% of the samples positive for co-presence of high-risk HPVs and EBV. Moreover, our data revealed that 5/70 (7%) samples are positive for MMTV. In addition, only 2/70 (3%) samples had co-presence of HPVs, EBV, and MMTV without any significant association with the clinicopathological variables. While, 6/16 (37.5%) controls were positive for HPV (p = .4), EBV was absent in all controls (0/16, 0%) (p = .01). In addition, we did not find the co-presence of the oncoviruses in the controls (p > .05). Nevertheless, further investigations are essential to understand the underlying mechanisms of multiple-oncogenic viruses' interaction in breast carcinogenesis, especially TNBC.

Cervical HPV type-specific pre-vaccination prevalence and age distribution in Croatia

The main etiological factor of precancerous lesion and invasive cervical cancer are oncogenic human papillomaviruses types (HPVs). The objective of this study was to establish the distribution of the most common HPVs in different cervical lesions and cancer prior to the implementation of organized population-based cervical screening and HPV vaccination in Croatia. In this study, 4,432 cervical specimens, collected through a 16-year period, were tested for the presence of HPV-DNA by polymerase chain reaction (PCR) with three sets of broad-spectrum primers and type-specific primers for most common low-risk (LR) types (HPV-6, 11) and the most common high-risk (HR) types (HPV-16, 18, 31, 33, 45, 52, 58). Additional 35 archival formalin-fixed, paraffin embedded tissue of cervical cancer specimens were analyzed using LiPA25 assay. The highest age-specific HPV-prevalence was in the group 18-24 years, which decreased continuously with age (P<0.0001) regardless of the cytological diagnosis. The prevalence of HR-HPV types significantly increased (P<0.0001) with the severity of cervical lesions. HPV-16 was the most common type found with a prevalence (with or without another HPV-type) of 6.9% in normal cytology, 15.5% in atypical squamous cells of undetermined significance, 14.4% in low-grade squamous intraepithelial lesions, 33.3% in high-grade squamous intraepithelial lesions, and 60.9% in cervical cancer specimens (P<0.0001). This study provides comprehensive and extensive data on the distribution of the most common HPV types among Croatian women, which will enable to predict and to monitor the impact of HPV-vaccination and to design effective screening strategies in Croatia.

Prevalence of DNA-HPV in male sexual partners of HPV-infected women and concordance of viral types in infected couples

Investigation of HPV infection in men remains important due to its association with genital warts and anorectal cancer, as well as to the role men play in HPV transmission to their female sexual partners. Asymptomatic men (n = 43), whose sexual partners had presented cervical HPV infection, were enrolled in this study. Among the 43 men, 23 had their female partner included and tested for HPV-DNA, totaling 23 couples. HPV-DNA was detected by PCR. Type specific PCR to detect HPV 16, 18, 31, 33, 45 and 6/11 was performed. At least one type of HPV was detected in 86.0% (37/43) of the male patients and more than one HPV type was identified in 39.5% (17/43) of the samples, including high and low risk HPV. HPV-16 proved to be the most prevalent viral type in both male and female samples. Concordance of at least one viral type was observed in 56.5% (13/23) of the couples. Among couples that have shown concordance of viral types, 84.6% (11/13) of the men had the same high risk viral type presented by the female sexual partner. These data suggest that HPV infected men is an important reservoir, contributing to a higher transmission to women and maintenance of infection, and consequently, a higher risk of developing cervical cancer. HPV vaccination in men will protect not only them but will also have implications for their sexual partners.

Detection and typing of human papillomaviruses combining different methods: polymerase chain reaction, restriction fragment length polymorphism, line probe assay and sequencing

The identification of the etiological factor of many cervical precancerous lesions and cervical cancer, the human papillomavirus (HPV) is widely used. In this study, we evaluated the consensus and type-specific (TS) polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), line probe assay (LiPA, Innogenetics) and sequencing to determine the HPV types in cervical specimens. Out of 690 High-grade Squamous Intraepithelial Lesion (HSIL) samples, 86.7% were HPV positive and 13.3% HPV negative by consensus primers (MY09/MY11, L1C1/L1C2-1/L1C2-2 and/or GP5/6) directed PCR. Out of 598 HPV positive samples, 85.3% were typed by TS-PCR being HPV 6/11, 16, 18, 31 and/or 33, while 14.7% remained untyped. The most prevalent HPV type in the study group was HPV 16, identified in 35.5% cases, while HPV 31 was the second most frequent HPV type with a prevalence of 10.5%. They were followed by HPV types 6/11, 33 and 18 with a prevalence of 7.4%, 6.2% and 4.9%, respectively. Multiple HPV infections with two or more HPV types (6/11, 16, 18, 31 and/or 33) were found in 9.4% cases. A subset of 88 samples was further typed by RFLP and LiPA to determine the rare HPV types in HSIL samples. The most frequent low abundant HPV types in single infections in decreasing order were HPV 53, 58, 66, 56 and 52, while HPV 51 was the most frequent low abundant HPV type found in multiple HPV infections. Multiple HPV infections were mostly found by LiPA in 27.3% cases versus 14.8% cases found by RFLP. The perfect agreement between RFLP and LiPA assay pair was observed only for HPV types 16, 18, 34 and 59 (kappa value of 1). For other HPV types, the inter-assay agreement ranged from very good to no agreement indicating that neither assay is perfect. Sequencing was performed for 33 samples in cases where both RFLP and LiPA were inconclusive. Sequencing was shown to be a very good method in case of single HPV infection but not applicable in case of multiple HPV infections. Both RFLP and LiPA are good assays for epidemiological studies, although RFLP being cumbersome and time-consuming is less applicable than LiPA. Careful consideration has to be made before the implementation of either HPV typing methods in clinical laboratories.

Molecular detection of HPV 16 and 18 in cervical samples of patients from Belo Horizonte, Minas Gerais, Brazil

PURPOSE

The aim of this study was to investigate the frequency of HPV infection and the types 16 and 18 in cervical samples from patients attended at two public health services of the city of Belo Horizonte, MG.

METHODS

Cervical samples from 174 patients were collected for cytopathological and molecular tests. HPV infection was searched by PCR utilizing MY09 and MY11 primers or HPV 16 and HPV 18 specific primers.

RESULTS

Amongst the 174 samples analyzed, 20.7% presented squamous intraepithelial and/or invasive lesions detected on cytopathological analysis and of those, 94.4% were infected by HPV. HPV 16 was found in 20% of the cases of low-grade squamous intraepithelial lesions and in 40% and 50% of high-grade squamous intraepithelial lesion and squamous invasive carcinoma, respectively. HPV 18 was detected in 6.7% of the low-grade lesion samples and in two HPV16 co-infected samples. In 50% of the cases of high-grade lesion, the HPV type was not determined.

CONCLUSION

The HPV 16 was the virus type more frequently detected. However, more than 50% of the positive samples at the cytopathological analysis were negative for HPV 16 and 18, indicating that possibly other virus types are present in relative high frequencies in the studied population.

Evaluation of different techniques for identification of human papillomavirus types of low prevalence

Human papillomaviruses (HPVs) have been recognized as etiologic factors in a variety of diseases. Due to the large number of HPV types, methods for HPV genotyping are difficult to standardize. Despite this fact, several methods exist, and some of them are available commercially. In this study, we evaluated the Roche Diagnostics linear array (LA) HPV genotyping assay, the Innogenetics INNO-LiPA (line probe assay [LiPA]), and two noncommercial reverse line blot (RLB) assays based on either primers GP5+ and GP6+ (GP) or newly designed broad-spectrum primers BSGP5+ and BSGP6+ (BS). The reliabilities of these assays were tested with a wide spectrum of HPV types less prevalent in cervical samples. This is the first study to compare the performance of the most widely used HPV genotyping methods with selected samples positive for low-prevalence HPV types. We focused on interassay agreement, both overall and type specific, in cases with single and/or multiple HPV infections. Interassay agreement was moderate in cases of single HPV infections and poor in cases of multiple HPV infections. The LA and the BS-based RLB assays found a higher rate of cases positive for multiple HPV types than LiPA and the GP-based RLB assay. The weakest capability in detecting multiple HPV infections was observed for LiPA. The use of only one assay in epidemiological and clinical studies might lead to biased conclusions. Therefore, a universally evaluated and agreed upon HPV typing assay or a combination of current assays is needed for possible clinical applications, and knowledge of their limitations is advised.

Validity of vaginal testing in detecting human papillomavirus (HPV) genotypes

The aim of this study was to assess the validity and usefulness of vaginal scrapes in detecting cervical human papillomavirus (HPV) DNA by the polymerase chain reaction (PCR). The study group comprised 23 women tested positive and 28 women tested negative for cervical HPV DNA by PCR, and confirmed by histopathology. At the time of specimen collection, both vaginal and endocervical scrapes were taken from these women, and tested for HPV DNA by PCR, using MY09/MY11 primer system. HPV genotypes were analyzed by hybridizing PCR products with HPV type-specific biotinylated probes. HPV DNA was detected in both vaginal and cervical scrapes from the HPV-positive, but not from HPV-negative group. In the HPV-positive group, the same HPV type was found in vaginal and endocervical scrapes, giving a positive predictive value of 1.0. The results indicate that HPV types can be detected in vaginal scrapes, and recommend utilization of the less invasive vaginal testing for the routine detection of HPV DNA.

Comparison of five different polymerase chain reaction methods for detection of human papillomavirus in cervical cell specimens

The polymerase chain reaction (PCR) methods enable the detection of large number of human papillomavirus (HPV) genotypes that infect the anogenital tract. In this study, two groups of cervical scrapes with abnormal cytomorphology were analysed. The first group was tested with three sets of consensus primers located within the L1 region of HPV genome, MY09/MY11 (i.e. MY), L1C1/L1C2-1/L1C2-2 (i.e. LC) and pI-1/pI-2 (i.e. pI) primer sets, while the second group of samples, which were all negative with the MY primers, was tested further with the LC primers, as well as with the GP5/GP6 (i.e. GP) primers. The GP primers were used in the nested PCR following amplification with the MY primers (i.e. MY/GP nested PCR). Samples from both groups were also tested with type-specific primers for HPV types 6/11, 16, 18, 31 and 33. In the first study group (N=164) there were 76.2% positive results obtained with at least one set of consensus primers. There were 62.2, 39, 62.2 and 59.1% positive results obtained with the MY, the pI, the LC and the HPV type-specific primer sets, respectively. The best results were obtained when both the MY and the LC primer sets were used, because in combination they detected 75% positive samples compared to 62.2% when used alone. There were 2. 4% samples negative with all consensus primers, but positive with one of the HPV type-specific primers, which increased the overall positivity rate to 78.6%. In the second study group (N=250) there were 8.4, 38.8 and 4% samples positive with the LC primers, the nested MY/GP and the HPV type-specific primer sets, respectively. Thus, the use of the MY/GP nested PCR increased significantly the positivity rate of HPV DNA detection and should be used for samples with a low copy number of HPV DNA. In conclusion, the following diagnostic protocol would be appropriate for detection of cancer-related HPVs: preselection of samples with the MY and the LC primers, additional amplification of the MY- and the LC-negative samples with the MY/GP nested PCR and HPV typing of consensus PCR-positive samples with the HPV type-specific primers.

Human papillomavirus genotype spectrum in Czech women: correlation of HPV DNA presence with antibodies against HPV-16, 18, and 33 virus-like particles

Because the biological spectrum of human papillomavirus (HPV) genotypes present in cervical cancer lesions varies according to the geographical region studied, and because little genotype information is available for Central and Eastern European countries, we studied the endemic HPV-genotype spectrum in cervical samples collected from women visiting gynaecological departments of selected hospitals in the Czech Republic. In a series of 389 samples, 171 (44.0%) were positive for HPV DNA using a consensus-primer polymerase chain reaction (PCR). Genotyping of the HPV PCR products was done using dot-blot hybridisation with type-specific oligonucleotide probes and thermocycle DNA sequencing. Twenty-two different HPV types were detected, HPV-16 being the most prevalent type irrespective of severity of the lesions (55.0%). Multiple HPV types were found in 16.4% of our HPV-DNA-positive samples. The prevalence of HPV infection was 23.0% in women with normal findings and 59.4% in patients with cervical neoplasia, and increased significantly with the severity of the disease: 52.9% in low-grade lesions, 58.0% in high-grade lesions, and 73.5% in cervical carcinomas (P for trend < .00001). In the sera of 191 subjects, 89 with normal findings and 102 with different forms of cervical neoplasia, the prevalence of HPV-specific IgG antibodies was tested by an enzyme-linked immunosorbent assay (ELISA) using virus-like particles (VLPs) of HPV-16, -18, and -33. Antibodies were significantly more prevalent in HPV-DNA-positive than in HPV-DNA-negative women and there was no association with age. In agreement with the results of HPV genotyping, antibodies reactive with HPV-16 VLPs were the most frequent and, moreover, their prevalence increased with the cervical lesion severity. About half of the subjects with smears in which either HPV-16 or HPV-33 DNA had been detected possessed antibodies reactive with homotypic VLPs. With HPV-18-DNA-positive subjects, however, fewer than 25% displayed homotypic antibodies. In general, subjects older than 30 years of age had antibodies reactive to HPV-specific VLPs more often than subjects younger than 30 years of age. In women with benign findings, the seropositivity to HPV-16, -18, and -33 VLPs increased with age, whereas in women with cervical neoplasia the seropositivity decreased with age.