Integration of human papillomavirus types 16 and 18 in cervical adenocarcinoma

HPV16 genome structure analysis in oropharyngeal cancer PDXs identifies tumors with integrated and episomal genomes

HPV + oropharyngeal squamous cell carcinoma (OPC) incidence recently surpassed cervical cancer and is the most common HPV-related cancer in the developed world. HPV16 is in ∼90 % of HPV + OPCs, with episomal genomes in the majority of cases. Most existing HPV16+ cancer cell lines derive from outside the oropharynx and harbor integrated HPV genomes. Thus, there is need for OPC preclinical models to evaluate standard and experimental therapeutics in the presence of episomal HPV16 oncogenic drivers. Here we characterize HPV genome structures in eight HPV16+ OPC patient-derived xenografts (PDXs), and evaluate their responses to standard chemotherapy. HPV genome state was investigated by combining Southern blot, T5 exonuclease assay, whole genome sequencing, and RNAseq data. This analysis revealed complexity and variation in integrated vs. episomal HPV forms across PDXs and demonstrated that four PDXs predominantly contain episomal HPV16. Episomal status did not ensure favorable in vivo responses to cisplatin therapy, despite the more favorable prognosis previously attributed to episomal HPV + tumors; this could be due to the small number present in the dataset. Our analysis establishes PDX models as test platforms for novel therapies designed to target maintenance of the episomal forms of HPV16 that commonly appear in OPC.

Prevalence and distribution of selected cervical human papillomavirus types in HIV infected and HIV uninfected women in South Africa, 1989-2021: A narrative review

Background

Human papillomavirus infection, a causative agent of cervical cancer, is of great concern, more so in populations with high HIV prevalence, such as South Africa.

Aim

This review aimed to examine the prevalence and distribution of selected cervical human papillomavirus (HPV) types in HIV infected and HIV uninfected women in South Africa.

Methods

PubMed and Web of Science databases were searched using key words. For data integrity, data was assessed by two authors independently. The study inclusion criteria comprised records on cervical HPV, HPV genotyping and HPV type distribution among South African women. Statistical analysis was performed using Social Science Statistics.

Results

Sixty-nine articles met the inclusion criteria for analysis. Data on cervical HPV prevalence and type distribution was available only for five of the nine provinces of South Africa. Only 4/69 studies used sequencing as an approach to identify HPV types. In a general population, HPV type 16 was the most frequent (8.80%), followed by types 35 (4.86%), 18 (4.14%), 58 and 52 with the frequency of 3.65% and 3.62%, respectively. Furthermore, the least frequent type was HPV 70 (0.74%). Both HIV infected and HIV uninfected populations had a higher prevalence of high-risk human papillomavirus (hrHPV) types 16, 18 and 35 than other HPV types; while HPV types 6, 11 and 70 were the least frequent types from these populations. Lastly, HPV 16 was the most predominant type among women with normal (2.03%) and abnormal cervical cytology (6.60%).

Conclusion

Expanding on HPV genotyping will improve the knowledge in patterns of HPV type distribution in South Africa that will further help in decision making to improve current diagnostics, and future vaccine development and assessment.

Viral Pathogens in Oesophageal and Gastric Cancer

Tumour virology was born with the discovery by Peyton Rous in 1911 of a filterable agent in chicken cellular extracts that caused neoplasia in healthy chickens. Universally, 20% of all human cancers have a viral aetiology. Viruses are involved at various stages of the carcinogenesis pathway, depending on the viral pathogen, and likely require co-factors. Multiple risk factors have been associated with oesophageal and gastric malignancy, including carcinogenic pathogens. These viruses and bacteria include human papillomavirus (HPV) [oesophageal cancer], Epstein-Barr virus (EBV) [proximal stomach cancer], and Helicobacter pylori (HP) [non-cardia stomach cancer]. Viruses such as EBV have been firmly established as causal for up to 10% of gastric cancers. HPV is associated with 13 to 35% of oesophageal adenocarcinoma but its role is unclear in oesophageal squamous cell carcinomas. The causal relationship between hepatitis B (HBV), cytomegalovirus (CMV), HPV, and John Cunningham (JCV) and gastric neoplasia remains indeterminate and warrants further study. The expression of viral antigens by human tumours offers preventive and therapeutic potential (including vaccination) and has already been harnessed with vaccines for HPV and HBV. Future goals include viral protein-based immunotherapy and monoclonal antibodies for the treatment of some of the subset of EBV and HPV-induced gastro-esophageal cancers.

Why Human Papillomaviruses Activate the DNA Damage Response (DDR) and How Cellular and Viral Replication Persists in the Presence of DDR Signaling

Human papillomaviruses (HPV) require the activation of the DNA damage response (DDR) in order to undergo a successful life cycle. This activation presents a challenge for the virus and the infected cell: how does viral and host replication proceed in the presence of a DDR that ordinarily arrests replication; and how do HPV16 infected cells retain the ability to proliferate in the presence of a DDR that ordinarily arrests the cell cycle? This raises a further question: why do HPV activate the DDR? The answers to these questions are only partially understood; a full understanding could identify novel therapeutic strategies to target HPV cancers. Here, we propose that the rapid replication of an 8 kb double stranded circular genome during infection creates aberrant DNA structures that attract and activate DDR proteins. Therefore, HPV replication in the presence of an active DDR is a necessity for a successful viral life cycle in order to resolve these DNA structures on viral genomes; without an active DDR, successful replication of the viral genome would not proceed. We discuss the essential role of TopBP1 in this process and also how viral and cellular replication proceeds in HPV infected cells in the presence of DDR signals.

Integration of Human Papillomavirus Genomes in Head and Neck Cancer: Is It Time to Consider a Paradigm Shift?

Human papillomaviruses (HPV) are detected in 70–80% of oropharyngeal cancers in the developed world, the incidence of which has reached epidemic proportions. The current paradigm regarding the status of the viral genome in these cancers is that there are three situations: one where the viral genome remains episomal, one where the viral genome integrates into the host genome and a third where there is a mixture of both integrated and episomal HPV genomes. Our recent work suggests that this third category has been mischaracterized as having integrated HPV genomes; evidence indicates that this category consists of virus–human hybrid episomes. Most of these hybrid episomes are consistent with being maintained by replication from HPV origin. We discuss our evidence to support this new paradigm, how such genomes can arise, and more importantly the implications for the clinical management of HPV positive head and neck cancers following accurate determination of the viral genome status.

Eleven-year review of data on Pap smears in Saudi Arabia: We need more focus on glandular abnormalities!

BACKGROUND

We reviewed data from Saudi Arabia on epithelial cell abnormalities (ECA) detected by Pap smear after noticing a slight increase in the incidence of cervical glandular abnormalities in our regional laboratory in recent years.

OBJECTIVE

Clarify data on adenocarcinoma (ADCA) on Pap smears in Saudi Arabia.

DESIGN

Descriptive, retrospective study.

SETTINGS

Regional laboratory, Riyadh.

PATIENTS AND METHODS

We reviewed all Pap smears of adult females between 2006 and 2016 and compared our data with previously published results from Saudi Arabia.

MAIN OUTCOME MEASURE(S)

Descriptive data on ECAs.

RESULTS

Among 19759 cases, atypical squamous cell of undetermined significance (ASC-US) was the most prevalent ECA (1.16%). ADCA occurred more than squamous cell carcinoma (SCC). In a comparison of published data before 2014 and after 2014 (including ours), there was a significant rise in ADCA (28 vs 48 cases; P=.004) with a significant drop in SCC, high-grade squamous intraepithelial lesions (HSIL) and low-grade squamous intraepithelial lesions (LSIL) (P < .0001, .004, and < .0001, respectively).

CONCLUSION

We recommend that pathologists and cytotechnologists be vigilant in screening Pap smears in our population, particularly for glandular abnormalities. We also recommend use of Pap smears in the initial workup of women with suspected gynecological abnormalities, regardless of evolutions in HPV testing.

LIMITATIONS

The pooling of data instead of analyzing by study year.

The complex relationship between human papillomavirus and cervical adenocarcinoma

Human Papillomavirus (HPV) is reported in 60-100% of cervical adenocarcinoma (CADC) globally. We investigated this relationship in a hospital-based survey in China. 718 CADC samples from nine Chinese regions were analysed. Expert pathologists reviewed cases with p16 and progesterone receptor immunostaining. Cases were tested for HPV using whole-tissue sections (WTS) and laser-capture microdissection. All cases were HPV-tested by L1 based broad-spectrum SPF10 -DEIA-LiPA25 PCR. Negative cases were tested for DNA adequacy and with E6 oncogene, type-specific HPV PCRs. Using WTS-PCR CADC showed overall 75% HPV-positivity (33-100% for different histological types). LCM-PCR showed that none of minimal deviation or serous CADC, and <10% of all clear cell and endometrioid CADC were HPV-positive in tumour cells. Usual and adenosquamous CADC showed a single HPV genotype in 60 and 78% cases. In some cases, HPV was found in adjacent cervix but not in tumour. HPV 16, 18 and 45 accounted for 90% of HPV in tumour cells. Patients with HPV-positive tumours were on average 6 years younger and presented at a lower clinicopathological stage as compared to patients with HPV-negative cancers. CADC is diverse pathologically and in HPV status. Special histopathological tumor subtypes may develop through different cellular and molecular pathways. Between 20 and 40% usual and adenosquamous types, in particular these diagnosed in older women and at advanced FIGO stages, are not driven by oncogenic HPV. In these cases HPV may not be involved in carcinogenisis or maybe lost during tumour progression.

HPV prevalence and genotypes in different histological subtypes of cervical adenocarcinoma, a worldwide analysis of 760 cases

The goal of our study was to provide comprehensive data on the worldwide human papillomavirus (HPV) genotype distribution in patients with invasive cervical adenocarcinoma in correlation with histologic tumor subtypes, geographical location, patients' age, and duration of sample storage. Paraffin-embedded samples of 760 cervical adenocarcinoma cases were collected worldwide. A three-level pathology review of cases was performed to obtain consensus histologic diagnoses and 682 cases were determined to be eligible for further analysis. HPV DNA detection and genotyping was performed using SPF-10/DEIA/LiPA(25) system (version 1). Classic cervical adenocarcinoma accounted for 83.1% of cases, while rare histological variants accounted for a few percent of cases individually. HPV positivity varied significantly between the different histologic tumor subtypes. Classic cervical adenocarcinoma showed high HPV positivity (71.8%), while other adenocarcinoma types had significantly lower HPV prevalence (endometrioid 27.3%, serous 25%, clear cell 20%, not otherwise specified 13.9%, and minimal deviation 8.3%). In all, 91.8% of HPV-positive tumors showed the presence of a single viral type and in 7% of cases multiple viral types were detected. Three HPV genotypes, HPV 16, 18, and 45, dominated in all adenocarcinomas and together accounted for 94.1% of HPV-positive tumors. HPV16 was the most common and found in 50.9% of HPV-positive cases, followed by HPV18 (31.6%) and HPV45 (11.6%). HPV prevalence varied depending on geographical region, patient age, and sample storage time. Tumors from older patients and tumor samples with longer storage time showed lower HPV prevalence. Our results indicate that HPV vaccines may prevent up to 82.5% (HPV16/18) and up to 95.3% (9-valent vaccine) of HPV-positive cervical adenocarcinomas, mostly the classic type. HPV testing and vaccination will not provide full coverage for a very small subset of classical adenocarcinomas and most of the rare tumor variants such as clear cell, serous, endometrioid, and minimal deviation.

Physical labeling of papillomavirus-infected, immortal, and cancerous cervical epithelial cells reveal surface changes at immortal stage

A significant change of surface features of malignant cervical epithelial cells compared to normal cells has been previously reported. Here, we are studying the question at which progressive stage leading to cervical cancer the surface alteration happens. A non-traditional method to identify malignant cervical epithelial cells in vitro, which is based on physical (in contrast to specific biochemical) labelling of cells with fluorescent silica micron-size beads, is used here to examine cells at progressive stages leading to cervical cancer which include normal epithelial cells, cells infected with human papillomavirus type-16 (HPV-16), cells immortalized by HPV-16, and carcinoma cells. The study shows a statistically significant (at p < 0.01) difference between both immortal and cancer cells and a group consisting of normal and infected. There is no significant difference between normal and infected cells. Immortal cells demonstrate the signal which is closer to cancer cells than to either normal or infected cells. This implies that the cell surface, surface cellular brush changes substantially when cells become immortal. Physical labeling of the cell surface represents a substantial departure from the traditional biochemical labeling methods. The results presented show the potential significance of physical properties of the cell surface for development of clinical methods for early detection of cervical cancer, even at the stage of immortalized, premalignant cells.

Primary signet-ring cell carcinoma of the cervix: case report and review of the literature

Mucinous adenocarcinoma of the cervix has 5 subtypes: endocervical, intestinal, signet-ring cell, minimal deviation, and villoglandular. There are only rare reports of primary signet-ring cell carcinoma of the cervix in the literature. Herein we report a 53-year-old woman with cervical adenocarcinoma with signet-ring cell morphology. Thorough systemic examination did not reveal another primary focus. DNA extraction from paraffin-embedded tissue revealed the presence of human papilloma virus (HPV) type 18, which supports the cervical origin of the tumor. Signet-ring cell morphology can be observed in both benign and malignant lesions of the uterine cervix. Most of the malignant lesions are metastatic. Histological features and immunohistochemical profiles are discussed, and a review of signet-ring cell morphology in the uterine cervix is included.

The prevalence of human papillomavirus type 58 in Chinese patients with cervical carcinoma and its influence on survival

AIMS

To assess the prevalence of human papillomavirus (HPV) type-specific infections and its influence on prognosis and survival rate of cervical cancer patients treated with radiotherapy alone or in combination with chemotherapy or hyperthermotherapy or both.

MATERIALS AND METHODS

During 1993 and 1994, 120 patients with cervical cancer were consecutively assigned into four therapeutic modalities. One hundred and eight formalin-fixed and paraffin-embedded tissue samples available at the time of this study were subjected to DNA extraction. The DNA was analysed for the presence of HPV and HPV type-specific infections with polymerase chain reaction. The experimental data were co-analysed with the follow-up data to evaluate prognosis and survival in relation to the HPV infection and treatment.

RESULTS

All samples were found to be positive for HPV; 32.40% (95% confidence interval 23.72-42.09) of samples were HPV 16 single positive, 16.67% (95% confidence interval 10.19-25.06) were HPV 58 single positive, 34.26% (95% confidence interval 25.4-44.01) were HPV 16/58 double positive and 16.67% (95% confidence interval 10.19-25.06) were positive for other HPV types. The 5-year survival rates were 88.89, 80.0, 67.57 and 61.11% in patients with HPV 58 single positive, HPV 16 single positive, HPV 16/58 double positive, and other HPV types, respectively (P=0.18), irrespective of the treatment modalities. Univariate Cox regression analysis results showed that compared with the HPV 16 single positive group, the relative risk of death was high in the HPV 16/58 double positive group (hazard ratio 1.81, 95% confidence interval 0.71-4.60) and the other HPV types group (hazard ratio 2.09, 95% confidence interval 0.73-5.96), whereas it was lower in the HPV 58 single positive group (hazard ratio 0.53, 95% confidence interval 0.11-2.56), but this was not statistically significant (P=0.43). All results remained statistically non-significant after adjustment for age and tumour stage with multivariate Cox regression. No apparent differences were observed in the survival rates among the four groups with regard to the treatment protocols.

CONCLUSION

No effect was seen of either treatment protocols or HPV type on survival, except for a slightly high survival in HPV 58 single-infected patients, which was statistically non-significant.

The natural history of cervical HPV infection: unresolved issues

The identification of high-risk human papillomavirus (HPV) types as a necessary cause of cervical cancer offers the prospect of effective primary prevention and the possibility of improving the efficiency of cervical screening programmes. However, for these opportunities to be realized, a more complete understanding of the natural history of HPV infection, and its relationship to the development of epithelial abnormalities of the cervix, is required. We discuss areas of uncertainty, and their possible effect on disease prevention strategies.

Non-neoplastic diseases of the cervix in Nigerians: a histopathological study

BACKGROUND

Diseases of the cervix are common in young sexually active women. Non-neoplastic diseases are predominantly inflammatory and are common but there are a few publications on the subject compared to neoplastic diseases of the cervix.

MATERIALS AND METHODS

The surgical day books of the Histopathology department of the Obafemi Awolowo University Teaching Hospitals Complex Ile-Ife, Nigeria from the year 1990-1999 (Ten years) were studied for all cervical biopsies.

RESULTS

Four hundred (400) cervical surgical biopsies were received during this period. 150 (37.5%) of the cases were non-neoplastic lesions. Age range was 20-69 years with peak incidence at 40-49 years. Histological distribution showed 123 cases (82%) were chronic non-specific cervicitis. Eighteen cases (12%) were chronic cervicitis with koilocytic change pathognomonic of Human Papilloma Virus (HPV) infection, two-third (12 cases) of which occur within 40-49 years. There were five cases (3.3%) of chronic granulomatous cervicitis, three cases (2.0%) of acute cervicitis and only one case (0.7%) of microglandular endocervical hyperplasia.

CONCLUSION

All the histological types were found within the peak age incidence of 40-49 years. Chronic non-specific cervicitis was the most common non-neoplastic cervical lesion and it occurs in all age groups of women studied. In 12% of patients it is associated with cytopathic effect of HPV. This has obvious implication for the occurrence of carcinoma of the cervix in our country. We recommend routine pap smear test in this group of patients especially, as a way of reducing the occurrence of carcinoma of the cervix.

Superficial (early) endocervical adenocarcinoma in situ: a study of 12 cases and comparison to conventional AIS

Although established histologic criteria for the diagnosis of endocervical adenocarcinoma in situ (AIS) have been published, some lesions are not readily classified or present with more subtle degrees of epithelial atypia. Lesions confined to the surface mucosa may be particularly challenging, possibly because they represent early disease. Twelve cases of superficial AIS (SAIS) confined to the surface mucosa or crypt openings culled from the in-house and consultation practices were examined histologically, immunostained for MIB-1 and p16, and analyzed (when possible) for HPV nucleic acids by DNA-DNA in situ hybridization (INFORM). The mean age was 26.7 years for SAIS versus 37.0 years for 42 consecutive cases of conventional AIS from the same practice (P < 0.001). Seven and five were biopsies and conization specimens, respectively. Five coexisted with CIN, four arose in endocervical papillae, and two arose in endocervical polyps. Nuclear hyperchromasia was conspicuous in 10 and mitoses were present in all; however, apoptosis was rare or absent in four, and six exhibited only mild nuclear atypia. Mib-1 staining exceeded 40% in 5 of 7 cases tested, and all (8 of 8) were strongly positive for p16(ink4). Five of five were positive for HPV by ISH with an "integrated" dot-like pattern. SAIS is an early variant of AIS that 1) occurs at a younger mean age, 2) exhibits variable atypia, and 3) arises adjacent to morphologically normal columnar epithelium. Diffuse p16 expression and integrated HPV pattern are identical to that seen in more extensive forms of the disease. Superficial AIS should be suspected in endocervical columnar epithelium with segmental nuclear hyperchromasia with mitotic activity, and confirmed by biomarker staining (p16 and Mib-1) if the pathologist is uncertain of the diagnosis.

Detection of human papillomavirus in large cell neuroendocrine carcinoma of the uterine cervix: a study of 12 cases

AIM

To investigate the role of human papillomavirus (HPV) in large cell neuroendocrine carcinoma (LCNEC) of the uterine cervix.

METHODS

Twelve archival, immunohistochemically and/or electron microscopically confirmed cases of cervical LCNEC were studied. Non-isotopic in situ hybridisation (NISH) was performed on the formalin fixed, paraffin wax embedded biopsies using digoxigenin labelled probes to HPV types 6, 11, 16, 18, 31, and 33. The tumours were then subjected to polymerase chain reaction (PCR) analysis using GP5+/GP6+ consensus primers to the HPV L1 gene, in addition to type specific primers to the E6 and E6/E7 genes.

RESULTS

HPV-16 was detected by NISH and/or PCR in seven of the 12 carcinomas. Two additional tumours were HPV-18 positive by NISH and/or PCR. HPV DNA was not detected in the three remaining cases.

CONCLUSION

Integration of high risk HPV, in particular type 16 and to a lesser extent type 18, is associated with this uncommon variant of cervical carcinoma.

Carcinosarcoma of the uterine cervix: a report of eight cases with immunohistochemical analysis and evaluation of human papillomavirus status

Carcinosarcomas (malignant Müllerian mixed tumors [MMMTs]) of the uterine cervix are rare neoplasms. This report describes the morphology, immunohistochemical profiles, and human papillomavirus (HPV) status of eight cervical MMMTs. Patients' ages ranged from 32 to 93 years (mean, 61 years). Seven cases showed in situ squamous cell carcinoma (SCC). The invasive epithelial component (EC) was composed of combined adenoid basal carcinoma, basaloid SCC, and adenoid cystic carcinoma (ACC) in two cases. Keratinizing SCC, large cell nonkeratinizing SCC, undifferentiated carcinoma, and basaloid SCC predominated in the remaining tumors, one of which had admixed ACC. The sarcomatous component (SC) was homologous and spindled with admixed myxoid areas in three lesions. The ECs and SCs in six MMMTs showed dual immunostaining with epithelial membrane antigen and the pan-keratin marker, MNF116. The SC was vimentin-positive in seven cases. Five tumors had a vimentin-positive EC. The SC was positive for muscle specific actin and/or smooth muscle actin in seven lesions, of which four were desmin-positive. Polymerase chain reaction (PCR) using GP5+/GP6+ L1 consensus primers detected HPV DNA in all eight cases. Nonisotopic in situ hybridization with digoxigenin-labeled probes to HPV types 6, 11, 16, 18, 31 and 33 demonstrated integrated HPV 16 in three cases, not only in the EC, but also in nuclei of the SC. This is the first study to implicate HPV in the evolution of cervical MMMTs. The above observations lend support to a metaplastic theory of histogenesis.

Well-differentiated villoglandular adenocarcinoma of the uterine cervix: oncogene/tumor suppressor gene alterations and human papillomavirus genotyping

Twelve well-differentiated villoglandular adenocarcinomas (WDVAs) of the uterine cervix were retrospectively analyzed for the presence and specific genotype of human papillomavirus (HPV), tumor suppressor loss (p53, MCC, APC, BRCA1), cancer gene mutation (K-ras-2, exons 1 and 2, p53 exons 5 to 8), and oncogene amplification (c-erbB-2/HER-2/neu, int-2). Tissue for genetic evaluation was obtained by microdissection, using 4-micron-thick histology sections of archival, formalin-fixed, paraffin-embedded specimens. Genotyping involved nucleic acid amplification and DNA sequencing with gene-specific oligonucleotides and L1 region consensus primers for common strains of HPV. Point mutation and HPV strain determination were accomplished by DNA sequence analysis. Tumor suppressor gene loss and oncogene amplification were performed by allelic imbalance analysis in informative subjects based on DNA sequence and microsatellite-length polymorphisms. HPV was present in all tumors and consisted of type 16 (n = 5, 42%) and type 18 (n = 7, 58%) strains, which have been closely associated with cervical neoplasia. K-ras-2 and p53 genes did not manifest point mutational damage. There was no evidence of oncogene amplification or tumor suppressor gene loss. The presence of HPV in all 12 tumors supports the role of HPV infection in the molecular pathogenesis of this uncommon neoplasm. The absence of associated oncogene or tumor suppressor gene damage is consistent with indolent biological behavior and the favorable prognosis of this unusual tumor.

Human papillomavirus types 16 E6 and E7 contribute differently to carcinogenesis

High-risk human papillomaviruses (HPVs) are etiologically implicated in human cervical cancer. Two viral genes, E6 and E7, are commonly found expressed in these cancer cells. We have previously shown that mice transgenic for the HPV-16 E6 gene or E7 gene, in which the E6 or E7 was expressed in the basal layer of epithelia, developed skin tumors. The spectrum of tumors derived from E6 and E7 mice differed, however; although most tumors derived from the E7-transgenic mice were benign, the majority of the tumors from the E6-transgenic mice were malignant. These findings led us to hypothesize that E6 and E7 play different roles in carcinogenesis. To assess at what stages in carcinogenesis E6 and E7 act, we treated the skin of K14E6- and K14E7-transgenic mice with chemical carcinogens known to contribute to distinct stages in carcinogenesis. Both E6 and E7 were found to synergize with chemical carcinogens in causing tumor formation. E6 was found to act weakly at the promotion stage of carcinogenesis in the formation of benign tumors but strongly at the progression stage which involves the malignant conversion of benign tumors. In contrast, E7 primarily affected the promotion stage of carcinogenesis. These results provide direct evidence that E6 and E7 contribute differently to carcinogenesis; E7 promotes the formation of benign tumors, and E6 acts primarily to accelerate progression of these benign tumors to the malignant stage. Consistent with this model, we found E6 and E7 to cooperate in inducing tumor formation in mice expressing both oncogenes.

Molecular events in uterine cervical cancer

OBJECTIVE

To review the literature regarding the molecular events which occur in the development of uterine cervical cancer, with particular reference to human papillomavirus (HPV) infection.

METHODOLOGY

Bibliographic searches of Medline and the ISI citation databases using appropriate keywords, including the following: papillomavirus, cervix, pathology, cyclin, chromosome, heterozygosity, telomerase, smoking, hormones, HLA, immune response, HIV, HSV, EBV.

CONCLUSIONS

It has become clear that most cervical neoplasia, whether intraepithelial or invasive, is attributable in part to HPV infection. However, HPV infection alone is not sufficient, and, in a small proportion of cases, may not be necessary for malignant transformation. There is increasing evidence that HPV gene products interfere with cell cycle control leading to secondary accumulation of small and large scale genetic abnormalities. This may explain the association of viral persistence with lesion progression but, in many patients, secondary factors, such as smoking and immune response, are clearly important. However, the mechanisms involved in the interaction between HPV and host factors are poorly understood.

Genotypic mapping of HPV and assessment of EBV prevalence in endocervical lesions

AIMS

To examine the prevalence of human papillomavirus (HPV) and Epstein-Barr virus (EBV) in low grade glandular intraepithelial lesions of the cervix, adenocarcinoma with high grade glandular intraepithelial lesions combined, and adenocarcinomas; and to perform a genotyping mapping analysis of endocervical carcinomas to determine the extent of HPV infections in such lesions.

MATERIAL

Archival paraffin wax embeded material from the files of the departments of pathology, National Maternity Hospital, Dublin, and University College Cork, Ireland.

METHODS

HPV prevalence was examined using type specific HPV PCR, general primer HPV PCR (pan HPV screen), nonisotopic in situ hybridisation (NISH), and PCR in situ hybridisation (PCR-ISH). In situ hybridisation was performed using fluorescein labelled oligonucleotide cocktail for eber transcripts of EBV. Genotypic analysis was performed, in all cases where possible, using a grid system.

RESULTS

HPV 16 and 18 were predominantly identified in low grade glandular intraepithelial lesions, high grade glandular intraepithelial lesions, and adenocarcinomas, with HPV prevalence increasing with grade of dysplasia. EBV was only identified in subepithelial lymphocytes in a minority of cases. No link could be shown between HPV and EBV in endocervical lesions. HPV infection was not clonal in endocervical cancer and coexistent adjacent cervical intraepithelial neoplasia, where present, tended to show a similar HPV type.

CONCLUSIONS

The restriction of HPV types 16 and 18 to endocervical lesions suggests that their effect is restricted and specific to endocervical mucosa, but the mechanism of interaction is currently unknown.

Detection of human papillomavirus DNA in genital lesions by enzymatic in situ hybridization with Fast Red and laser scanning confocal microscopy

Human papillomavirus (HPV) infection with potentially oncogenic types 16 or 18 is common in genital lesions especially in uterine carcinomas. In such lesions, in situ hybridization with non-radioactive probes is a powerful tool for the histopathologist to detect and type HPV DNA either on cell deposits or on tissue sections. The use of an immunohistochemical method involving alkaline phosphatase and Fast Red TR salt/naphthol AS-MX phosphate is proposed for use with conventional bright-field or fluorescence microscopy as well as by laser scanning confocal microscopy. The alkaline phosphatase-Fast Red reaction has the advantage of producing a red precipitate that permits the detection of in situ hybridization signals by bright-field microscopy, and of obtaining a strong red fluorescence characterized by a lack of bleaching when excited by a green light. Therefore, the alkaline phosphatase-Fast Red reaction is well adapted for observations by fluorescence and confocal microscopy, the latter method allowing the detection, in tissue sections of cervical intraepithelial lesions, of small punctate and large diffuse hybridization signals, considered as integrated and episomal states of HPV DNA respectively. The combination of in situ hybridization with the alkaline phosphatase-Fast Red reaction and confocal microscopy is particularly convincing when hybridization signals are of small size and/or of low fluorescence intensity, especially if they are present in various focal planes; in such conditions, infected cells are easily detected by three-dimensional reconstruction. Therefore, this combination is a suitable method for identifying and characterizing HPV DNA in cells and tissue sections.

Detection of integrated high risk human papillomavirus in adenoid cystic carcinoma of the uterine cervix

AIM

To investigate the role of human papillomavirus (HPV) in adenoid cystic carcinoma of the uterine cervix.

METHODS

Eleven archival, paraffin wax embedded specimens were analysed by non-isotopic in situ hybridisation (NISH) for HPV types 6, 11, 16, 18, 31, and 33 using digoxigenin labelled probes. The polymerase chain reaction (PCR) was carried out on each of the cases using consensus primers to HPV.

RESULTS

A total of eight adenoid cystic carcinomas harboured the HPV genome by NISH, of which five were PCR positive. Integrated HPV 16 DNA was demonstrated in seven of the eight NISH positive cases. One adenoid cystic carcinoma showed integrated HPV 31. HPV DNA was not detected in the three remaining cases.

CONCLUSIONS

Integrated high risk HPV genome, in particular type 16, is associated with this uncommon type of primary cervical cancer.

Sexually transmitted diseases in South Africa

AIM

To review the epidemiology of and data collection for sexually transmitted diseases (STDs) in South Africa.

METHODS

Literature published since 1980 on STDs in South Africa were complied and evaluated. Historical reports and salient unpublished literature were also used in the literature review. Studies were critically reviewed in the light of sample populations and study methods, and a baseline picture of the patterns of STD burden was developed.

RESULTS

The STD burden in apparently asymptomatic study populations is significant. Ulcerative infections, primarily caused by syphilis and chancroid, are present in 5-15% of asymptomatic clinic attenders; prevalence rates of gonorrhoea average 8%, with up to 13% of gonococcal isolates resistant to penicillin antibiotics. In addition, on average, chlamydia and vaginal infections are detected in 16% and 20-49%, respectively, of antenatal and family planning clinic attenders. HIV seroprevalence rates have reached 7.6% in antenatal clinic attenders. Most South African STD data are derived from ad hoc surveys which have traditionally focused only on several major infections and particular urban centres. Almost all STD studies have been facility-based, with many studies based at STD clinics, thus reporting only relative frequencies and not population-based prevalences of STDs. With the possible exception of HIV, systematic surveillance data for STDs are conspicuously lacking.

CONCLUSION

The disease burden of classic sexually transmitted infections has historically been heavy, and continues to be a serious public health problem in South Africa. Morbidity from both ulcerative and non-ulcerative infections, particularly in women, is significant. The body of STD data, although mostly sound, remains incomplete, and with the rapid emergence of HIV in South Africa, surveillance of STDs and focused STD policies will be critical.

Persistence of human papillomavirus (HPV) infections preceding cervical carcinoma

BACKGROUND

A persistent genital infection with an oncogene-type of human papillomavirus (HPV) is considered to be essential for the development of most cervical carcinomas. Therefore, HPV analysis has been proposed as a possible complementary cytological screening program. The authors have developed a technique to analyze archival Pap smears, which has enabled them to study the relation between persistent HPV infection and the development of cervical cancer.

METHODS

Nested polymerase chain reaction was used to demonstrate the presence of HPV DNA, and sequencing of the obtained amplimer was performed to establish HPV type. The authors analyzed a series of 88 smears taken 1.5 to 7 years prior to the diagnosis of an HPV-containing cervical carcinoma (12 invasive adenocarcinomas, 18 invasive squamous carcinomas, and 58 squamous carcinoma in situ), which were compared with age-matched controls with no tumor development.

RESULTS

HPV DNA was present in a majority of the smears preceding a cancer, with an odds ratio of around 15 for all tumor groups. Infections with a persisting HPV type were demonstrated in most samples from a series of eight patients, from who multiple smears were available, covering the 7-year period preceding the cancer diagnosis.

CONCLUSIONS

Persisting infection can be demonstrated in exfoliated cells many years before cancer is diagnosed. The results are complementary to those obtained with cytology, that is, HPV is detected also in those at-risk patients whose Pap smears are morphologically normal. However, the results are still insufficient to justify a general recommendation to use HPV testing for health control purposes.

Criteria for consistent and high sensitivity of DNA in situ hybridization on paraffin sections: optimal proteolytic enzyme digestion

It is technically challenging for the detection of target DNA in low abundancy, such as viral DNA sequences in latently infected cells by nonisotopic in situ hybridization (ISH). Consistent result is even more difficult to achieve on routine paraffin sections. Proteolytic enzyme digestion is most critical for both consistency and sensitivity of the technique. We here have investigated the effect of enzyme digestion on cell morphology, protein and DNA reduction, and hybridization efficiency. The results demonstrated that enzyme digestion improves efficiency of ISH through a process involving partial DNA purification on sections. There is a clear relationship between proteolytic enzyme digestion, morphology changes, and hybridization efficiency. Although detection of DNA sequences in abundance can be achieved within a relatively wide range of digestion levels, maximum hybridization efficiency was always related to the cells, which showed morphology of nuclear swollen, weak homogeneous chromatin staining with hematoxylin and loss of visible nuclear membrane. Detection of viral DNA in low copy number critically depends on the creation of the morphologic changes by enzyme digestion. The morphological changes would therefore serve as important criteria for optimal digestion, result interpretation, and comparison.

Human papillomaviruses and cervical neoplasia. I. Classification, virology, pathology, and epidemiology

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Human papillomavirus type 18 associates with more advanced cervical neoplasia than human papillomavirus type 16

A type-specific, sensitive, polymerase chain reaction-based assay for human papillomavirus (HPV) types 6b, 11, 16, 18, and 33 was applied to 47 cervical carcinomas, 60 cases of cervical intraepithelial neoplasia (CIN), and 24 samples of histologically normal cervix. As expected, the combined incidence of the common high-risk genital HPVs (types 16 and 18) was high in carcinomas (79%) and CIN 2/3 (60%), low in CIN 1 (25%), and nonexistent in the normal controls. Analysis of the data by viral type and pathology revealed statistically significant differences that consistently pointed to an association of HPV 18 with more advanced disease than HPV 16. This was exemplified by calculation of the relative HPV frequency in squamous cancers and CIN 2/3 lesions, which gave cancer to CIN prevalence ratios of 1.2 for HPV 16 and 2.3 for HPV 18, a twofold difference suggesting the possibility that there is a greater risk of progression or a more rapid transition to malignancy associated with HPV 18. Furthermore, HPV 16 was associated with 2.5-fold more cancers showing squamous differentiation (58%) than HPV 18 (23%), but both types showed an identical prevalence of 41% in the clinically more sinister adenocarcinomas, indicating that there may be an association between HPV type and cancer cell differentiation.