Carol H. Thompson

Human papillomavirus positivity predicts favourable outcome for squamous carcinoma of the tonsil

Mutations in the p53 and retinoblastoma (pRb) pathways associated with the use of tobacco and alcohol are common in squamous cell carcinoma (SCC) of the head and neck. Cell cycle proteins are also affected by human papillomavirus (HPV), which may also have an aetiological role in cancers at particular sites, most notably the tonsil. Attempts to identify prognostic molecular markers in head and neck cancers have met with conflicting results, but few studies have been undertaken with tumours of known HPV status at a single anatomic site. In our study 86 tonsil cancers were analysed for HPV status by sequence analysis of polymerase chain reaction products and for the expression of cell cycle proteins (p53, p21CIP1/WAF1, pRb, p16INK4A, cyclin D1 and p27KIP1) by immunohistochemistry. The HPV status could be established in 67 of the tumours. Thirty‐one (46%) of these were HPV‐positive, predominantly (28/31) for HPV16. Findings were related to tumour recurrence and patient survival. None of the cell cycle proteins independently predicted recurrence or survival. Patients with HPV‐positive tumours, however, were significantly less likely (p < 0.05) to have recurrence or to die of disease than those with HPV‐negative tumours, after adjusting for the effects of the cell cycle proteins, clinical stage, pathological node status, tumour grade, age, gender and treatment. These findings support the concept that HPV‐positive tonsil cancers may be a distinct biological group with less aggressive characteristics. Screening of tonsil cancers for HPV DNA may help optimise treatment and provide more accurate prognostic information.

The Expression Of Key Cell Cycle Markers And Presence Of Human Papillomavirus In Squamous Cell Carcinoma Of The Tonsil.

Chemical carcinogens induce squamous cell carcinoma (SCC) of the head and neck by targeting the p53 and the retinoblastoma (pRb) pathways. Human papillomavirus (HPV) might have an etiologic role in these cancers at particular sites. Few studies have compared cell cycle protein expression in HPV‐positive and HPV‐negative tumors in this region.

Molluscum Contagiosum Virus: Antibody Responses in Persons with Clinical Lesions and Seroepidemiology in a Representative Australian Population

An ELISA for molluscum contagiosum virus (MCV) was used to determine the antibody status of 35 adults with clinical infections and known human immunodeficiency virus (HIV) serology and of 357 persons (ages, 1 week-69 years) considered representative of the Australian population. MCV antibody was identified in 77% of persons with molluscum lesions: in 17 of 24 HIV-1-negative persons and in 10 of 11 who were HIV-1-positive. No relationship was evident between the serologic responses and the number of lesions or the duration of infection. The population survey revealed an overall seropositivity rate of 23%. The lowest antibody prevalence was in children aged 6 months to 2 years (3%), and seropositivity increased with age to reach 39% in persons >/=50 years old. These findings indicate that MCV infections, including very mild or subclinical cases, may be more common in the general community than previously suspected.

Human papillomavirus deoxyribonucleic acid as a prognostic indicator in early-stage cervical cancer: A possible role for type 18☆

OBJECTIVE Our purpose was to determine the prognostic significance of human papillomavirus deoxyribonucleic acid in cervical cancers. STUDY DESIGN The polymerase chain reaction was used to detect human papillomavirus deoxyribonucleic acid types 6, 11, 16, 18, 31, 33, 52, or 58 in tumors from 148 patients (equal numbers of whom were disease free or had relapses) surgically treated for stage IB or IIA cancers in a major Australian hospital. Cox regression modeling was used to assess the effect of human papillomavirus status on tumor recurrence, taking into account patient age, clinical stage, histologic node status, and type of tumor. RESULTS Seventy of 74 (95%) of the recurring tumors and 62 of 74 (84%) of the nonrecurring tumors were human papillomavirus deoxyribonucleic acid positive. The rates of positivity of types 16 and 18 were 64% versus 31% in the recurrers and 65% versus 14% in the nonrecurrers. Human papillomavirus type 18 positivity was associated with a greater risk of recurrence than was type 16 positivity (hazard ratio 1.8; p = 0.03). Clinical stage, nodal metastasis, and young age (< or = 35 years) also had adverse effects on relapse (hazard ratio for each approximately 2). CONCLUSION Human papillomavirus type 18 positivity is a risk factor for tumor recurrence in surgically treated cervical cancer.

Analysis of mutations in the URR and E6/E7 oncogenes of HPV 16 cervical cancer isolates from central China.

High rates of cervical cancer have been reported from parts of China and this may reflect a predominance of cervical infection with particularly aggressive human papillomavirus (HPV) variants. This PCR‐based investigation of cervical tumours from Sichuan province in central China demonstrated an HPV positivity rate of 88%. HPV 16 was most common (21/34, 61%), followed by HPV 18 (3/34, 9%), while types 33, 45, 58 and 59 were each identified in one specimen. Sequencing of up to 1349 bases of the 21 HPV 16‐positive isolates, encompassing the enhancer/promoter of the upstream regulatory region (URR) and the E6 and E7 genes, revealed distinct patterns of genomic stability and variability. An overall mutation rate of 5% was seen in the URR. One isolate had a large deletion of 436 bases in the enhancer; while varying combinations of 21 point mutations were identified in the remainder, impacting several YY1, NF1, TEF‐1 and Oct‐1 sites. More sequence variations were found in E6 compared to E7 (81% vs. 52% of isolates showing at least one mutation), some of which resulted in changes to the translated amino acids. Since the E6/E7 genes encode the oncogenic proteins essential for malignant transformation, and as their expression is controlled by the URR, it is possible that some of the identified mutations altered the oncogenicity of the virus: either directly by changing amino acid sequences of the E6 or E7 oncoproteins, or indirectly through alterations to transcription factor binding sites in the URR. Int. J. Cancer 86:695–701, 2000.

Absence of human papillomavirus in tonsillar squamous cell carcinomas from Chinese patients.

Epidemiological and experimental evidence from Western countries now consistently support an etiological role for human papillomavirus (HPV) in a subset of oropharyngeal squamous cell carcinomas (SCC), especially those originating in the tonsil. The role of HPV in the etiology of tonsil cancer in developing countries such as China has not been investigated. In this study, none of 16 tonsil cancer specimens from Chinese patients were positive for HPV DNA, whereas those from Australian patients using the same methodology gave a positivity rate of 46%. The tumors from Chinese patients, like the Australian HPV-negative subset, significantly overexpressed pRb and cyclin D1 and underexpressed p16(INK4A) (p16). In contrast, the Australian HPV-positive cancers overexpressed p16 and had reduced expression of pRb and cyclin D1. These findings may help explain why China has a relatively low rate of oropharyngeal cancer compared with Australia. They also support the hypothesis that molecular pathways to tonsil cancer mediated by HPV are distinct from those induced by mutagens present in cigarette smoke or alcohol.

Sequence variation and physical state of human papillomavirus type 16 cervical cancer isolates from Australia and New Caledonia

Sequence diversity over 2600 nucleotides of the upstream regulatory region (URR) and the E6 and E2/E4 genes of 34 human papillomavirus (HPV)16 cervical cancer isolates from Australia and New Caledonia was investigated. One 81 base duplication, 41 single base substitutions and 1 single base insertion were identified in the URRs. Some of these changes are reported here for the first time. Several of the 19 changes impacting transcription factor binding sites had the potential to alter promoter activity. Twenty‐eight (82%) of the variants belonged to the European lineage, 4 (12%) were Asian and 2 (6%) were Asian‐American. Eighteen of 27 (67%) isolates where the E6 gene was examined contained amino acid substitutions. Of 13 isolates sequenced with intact E2 genes, 12 (92%) contained amino acid substitutions in the E2 protein and 3 (23%) amino acid substitutions in the overlapping E4 protein. Some of the changes in E6 and E2 may alter immunological epitopes or protein function. The physical state of HPV DNA was assessed by Southern hybridization and PCR for an intact E2 gene. Overall, 11 of 25 isolates contained only integrated HPV DNA, 10 only episomal HPV DNA and 4 both integrated and episomal DNA. No particular patterns of variation in the URR, E6 or E2/E4 genes predicted physical state. This investigation represents one of the most comprehensive studies of its kind and fills an important gap in global sequence data.

Identification and typing of molluscum contagiosum virus in clinical specimens by polymerase chain reaction

A polymerase chain reaction (PCR) which enables the detection of molluscum contagiosum virus (MCV) genomes in either fresh or formalin‐fixed clinical specimens is described. The primers used were designed to amplify a 167 bp region of the 3.8kbp HindIII fragment K of the MCV 1 genome. The ability of this PCR to detect three common MCV types (1, 1v and 2) in clini‐cal specimens was confirmed using frozen extracts from 75 molluscum lesions, and digests of single sections of 11 formalin‐fixed, paraf‐fin‐embedded lesions; all of which had been previously typed by Southern hybridisation. In addition, 2 specimens previously negative by hybridisation were shown to be positive for MCV DNA by PCR. Confirmation of the identity of the PCR products and distinction between the two major MCV types (MCV 1/1v versus MCV 2) was achieved by comparison of the results of cleavage with the restriction endonucleases HhaI and SacI. Sequencing of the PCR products revealed complete homology between MCV 1 and 1v, but minor nucleotide variations between MCV 1/1v and MCV 2 were identified. As well as providing a highly sensitive means of diagnosis, the technique may also prove useful for investigations into the pathogenesis, epidemiology and natural history of molluscum contagiosum infection. J. Med. Virol. 53:205–211, 1997.

Factors associated with clinical and sub-clinical anal human papillomavirus infection in homosexual men.

OBJECTIVES--(I) to determine the relative sensitivities of clinical examination, cytology and HPV DNA hybridisation for the detection of anal human papillomavirus infection; and (ii) to examine various factors which may influence presentation of anal human papillomavirus infection in homosexual men. METHODS AND RESULTS--112 unselected homosexual men attending a Sydney STD clinic for routine screening underwent a complete anogenital and physical examination, during which blood samples (for haematological, serological and immunological investigations), rectal swabs (for culture of anal pathogens) and anal scrapes of the dentate line (for cytology and HPV DNA hybridisation) were collected. Papanicolaou-stained anal smears were examined for cytological abnormalities, including those indicative of HPV infection or anal intraepithelial neoplasia (AIN). HPV DNA was detected by high stringency dot hybridisations using radiolabelled HPV 6, 11, 16 and 18 DNA probes. Visible anal condylomata, situated either externally or in the anal canal, were present in 26% of these men; 46% had cytological evidence of HPV infection, and 19% of the smears showed evidence of mild to moderate dysplastic changes (AIN I-II). Detectable HPV DNA was present in 40% of the anal scrapes. By combining these results, a total of 73 men (65%) were found to have at least one of the indicators of HPV infection. These data, together with that relating to HIV antibody, immune status and past or present infection with other STDs, was correlated with information obtained from a questionnaire administered to the patients at the time of their clinical examination. CONCLUSIONS--In this study cytology was found to be slightly more sensitive than HPV DNA dot hybridisation for the detection of HPV infection in the anal canal, providing the full range of HPV-associated cytological changes were accepted as a basis for diagnosis. Clinical anal lesions were more likely to be detected in young men, men who had symptomatic HIV infection and those with a history of past anal wart infection. The latter group also had a higher incidence of cytologically apparent HPV infection in their anal smears. There was a significant association between the detection of HPV 16/18 and the presence of anal dysplasia, but there were no significant correlations between HPV infection or anal dysplasia and HIV antibody, immune function status, sexual practices or history of other STDs.

Clinical and molecular aspects of molluscum contagiosum infection in HIV-1 positive patients.

Molluscum contagiosum virus (MCV) lesions from 31 human immunodeficiency type 1 (HIV-1) positive patients and 54 HIV-1 negative adult control patients were examined for the presence and type of MCV DNA by high stringency Southern hybridization using 32P-labelled or digoxigenin-labelled MCV DNA probes. Of the 83 patients whose lesions contained detectable MCV DNA, 77 were infected with a single type of MCV (16 with MCV 1; 29 with MCV 1v; 30 with MCV 2; and 2 with MCV 2v). Five patients had apparent double infections, with hybridization results indicating the presence of various combinations of MCV 1 or lv and MCV 2 or 2v. When these results were analysed in the light of clinical data no correlations were found between the MCV type(s) detected and the clinical stage of HIV-1 infection; nor between the MCV types and the anatomical site of the lesions or persistence of infection. However, the HIV-1 positive patients were significantly more likely to be infected with MCV types 2 or 2v than were the controls (17/29, 59% versus 15/48, 31%; P<0.05). Since a concurrent study of MCV lesions in children aged 15 years or less has shown that the percentage of infections attributable to MCV 2 or 2v is extremely small (3%), this finding suggests that MCV lesions in HIV-1 positive patients are attributable to adult-acquired MCV infection rather than to reactivation of a childhood infection.