Human papillomavirus positive squamous cell carcinoma of the oropharynx: a radiosensitive subgroup of head and neck carcinoma

Identification of biomarkers that distinguish human papillomavirus (HPV)-positive versus HPV-negative head and neck cancers in a mouse model

Head and neck squamous cell carcinoma (HNSCC) is a leading cause of cancer mortality worldwide. Recent reports have associated a subset of HNSCC with high-risk human papillomaviruses (HPVs), particularly HPV16, the same subset of HPVs responsible for the majority of cervical and anogenital cancers. In this study we describe a mouse model for HPV-associated HNSCC that employs mice transgenic for the HPV16 oncogenes E6 and E7. In these mice, E6 and E7 induce aberrant epithelial proliferation and, in the presence of a chemical carcinogen, they increase dramatically the animal's susceptibility to HNSCC. The cancers arising in the HPV16-transgenic mice mirror the molecular and histopathological characteristics of human HPV-positive HNSCC that distinguish the latter from human HPV-negative HNSCC, including overexpression of p16 protein and formation of more basaloid cancers. This validated model of HPV-associated HNSCC provides the means to define the contributions of individual HPV oncogenes to HNSCC and to understand the molecular basis for the differing clinical properties of HPV-positive and HPV-negative human HNSCC. From this study, we identify minichromosome maintenance protein 7 (MCM7) and p16 as potentially useful biomarkers for HPV-positive head and neck cancer.

Clinical implications of human papillomavirus in head and neck cancers

Human papillomavirus (HPV) is now recognized to play a role in the pathogenesis of a subset of head and neck squamous cell carcinomas (HNSCCs), particularly those that arise from the lingual and palatine tonsils within the oropharynx. High-risk HPV16 is identified in the overwhelming majority of HPV-positive tumors, which have molecular-genetic alterations indicative of viral oncogene function. Measures of HPV exposure, including sexual behaviors, seropositivity to HPV16, and oral, high-risk HPV infection, are associated with increased risk for oropharyngeal cancer. HPV infection may be altering the demographics of HNSCC patients, as these patients tend to be younger, nonsmokers, and nondrinkers. There is sufficient evidence to conclude that a diagnosis of HPV-positive HNSCC has significant prognostic implications; these patients have at least half the risk of death from HNSCC when compared with the HPV-negative patient. The HPV etiology of these tumors may have future clinical implications for the diagnosis, therapy, screening, and prevention of HNSCC.

HPV infection in relation to OSCC histological grading and TNM stage. Evaluation by traditional statistics and fuzzy logic model

We aimed to evaluate if in oral squamous cell carcinoma (OSCC) there is a relationship between histological grading (HG), TNM clinical stage and HPV infection; and to study the performance of fuzzy logic compared to traditional statistics, in the analysis of HPV status and correlates of OSCC. In cross-sectional analysis, the study group comprised 63 patients (mean age 68.89 years (SD +/-11.78), range (32-93); males 28 (44.4%), females 35 (55.6%)) with OSCC histologically diagnosed. HPV-DNA was studied in exfoliated oral epithelial cells by nested PCR (MY09/MY11 and GP5+/GP6+ primers). Data were analysed in parallel by traditional statistics with multivariate analysis and a fuzzy logic (FL) technique (membership functions as input, the ANFIS methodology, and the Sugeno's model of first order). HPV infection was detected in 24/63 (38.1%) of OSCC, as being HPV+ve 14/36 (38.9%) in G1, 7/18 (38.9%) in G2, and 3/9 (33.3%) in G3; HPV+ve 8/33 (24.2%) in Stage I, 9/12 (75.0%) in Stage II, 6/11(54.5%) in Stage III, and 1/7 (14.3%) in Stage IV. In both methods of analysis, no significantly increased risk of HPV infection was found for any HG score; whereas, TNM stage II was significantly associated to HPV infection (p=0.004; OR=9.375 (95% CI=2.030:43.30); OR'=11.148 (95% CI=1.951:43.30)), and, in particular, to primary tumour size T2 (p=0.0036; OR=7.812 (95% CI=1.914:31.890); OR'=9.414 (95% CI=1.846:48.013)); FL (% of prevision: 79.8; Root Mean-Square Error (RMSE): 0.29). No association was found between HPV infection and any demographical variable. Our findings show an association between HPV infection with TNM (stage II-T2), but not with histological grading of OSCC. Also, FL seems to be an additional effective tool in analysing the relationship of HPV infection with correlates of OSCC.

The role of human papillomavirus in squamous carcinoma of the head and neck

Human papillomavirus type-16 infection is associated with a significant portion of squamous carcinoma of the head and neck, particularly for the oropharynx and for those lacking the other risk factors of tobacco and alcohol. The link between human papillomavirus type-16 and carcinoma of the oropharynx is based on the identification of human papillomavirus type-16 in oropharyngeal tumors and the association of human papillomavirus type-16 with the risk of oropharyngeal cancer estimated in case-control epidemiologic studies. This review highlights the molecular mechanism of human papillomavirus carcinogenesis and the association of human papillomavirus type-16 as a risk factor for squamous cell carcinoma of the oropharynx as well as recent research efforts utilizing human papillomavirus as a biomarker of clinical outcomes.

The prevalence of human papillomavirus in the oropharynx in healthy individuals in a Brazilian population

Oncogenic human papillomavirus (HPV), a causative agent of uterine cervical cancer, has also been detected in head and neck squamous cell cancers, especially in squamous cell carcinomas of the tonsils. However, the true HPV prevalence in normal and neoplasic oropharyngeal mucosa remains uncertain. To determine the prevalence of HPV DNA in normal oropharyngeal mucosa of cancer-free individuals, a study was carried out on 50 Brazilian subjects. PCR was performed to identify HPV DNA in samples from four sites in the oropharynx (tonsils, soft palate, base of the tongue, and back wall of the pharynx). For amplification of the HPV DNA, MY09/11 consensus primers were used, and specific genotypes were identified by dot-blot hybridization or cloning and sequencing. HPV DNA was present in 14.0% of the individuals, and the identified genotypes were 16, 18, 52, and 61. All these types are considered high-risk (HR) HPV. The tonsils and the soft palate were the sites with the highest HPV prevalence. This study shows the prevalence of HR HPV in the oropharynx of normal individuals. However, the prevalence of HPV is still unclear, and if HPV infection in a healthy it is not known individual predisposes to HPV-associated disease such as oropharyngeal cancer. Thus, it is important to assess the prevalence of HPV in cancer-free individuals, in order to compare it with the HPV prevalence in oropharyngeal carcinomas and to attempt to determine the true role of HPV in the development of head and neck squamous cell cancers.

Impact of viral E2-gene status on outcome after radiotherapy for patients with human papillomavirus 16-positive cancer of the uterine cervix

PURPOSE

Integration of high-risk papillomavirus DNA has been considered an important step in oncogenic progression to cervical carcinoma. Disruption of the human papillomavirus (HPV) genome within the E2 gene is frequently a consequence. This study investigated the influence of episomal viral DNA on outcome in patients with advanced cervical cancer treated with primary radiotherapy.

METHODS AND MATERIALS

Paraffin-embedded biopsies of 82 women with locally advanced cervical cancer could be analyzed for HPV infection by multiplex polymerase chain reaction (PCR) by use of SPF1/2 primers. E2-gene intactness of HPV-16-positive samples was analyzed in 3 separate amplification reactions by use of the E2A, E2B, E2C primers. Statistical analyses (Kaplan-Meier method; log-rank test) were performed for overall survival (OS), disease-free survival (DFS), local progression-free survival (LPFS), and distant metastases-free survival (DMFS).

RESULTS

Sixty-one (75%) of 82 carcinomas were HPV positive, 44 of them for HPV-16 (72%). Seventeen of the 44 HPV-16-positive tumors (39%) had an intact E2 gene. Patients with a HPV-16-positive tumor and an intact E2 gene showed a trend for a better DFS (58% vs. 38%, p = 0.06) compared with those with a disrupted E2 gene. A nonsignificant difference occurred regarding OS (87% vs. 66%, p = 0.16) and DMFS (57% vs. 48%, p = 0.15).

CONCLUSION

E2-gene status may be a promising new target, but more studies are required to elucidate the effect of the viral E2 gene on outcome after radiotherapy in HPV-positive tumors.

Human papillomavirus (HPV)-related oropharyngeal nonkeratinizing squamous cell carcinoma: characterization of a distinct phenotype

We have recently shown that HPV-positive tonsillar carcinoma in young patients exhibits nonkeratinizing basaloid morphology and a characteristic immunophenotype. The purpose of this study was to review a large number of cases of oropharyngeal carcinomas, in all age groups, and to identify tumors with nonkeratinizing morphology. Using polymerase chain reaction (PCR) the prevalence and type of HPV DNA was determined in representative cases and in a control group of conventional keratinizing squamous cell carcinomas. The tumors were further characterized with a panel of immunohistochemical stains. A total of 235 carcinomas were reviewed; 141 of the tonsils and 94 in the base of tongue. Ninety (36%) of the tonsillar and 30 (32%) of the base of tongue carcinomas were nonkeratinizing (NKCa) with basal cell features; the rest were classical keratinizing squamous cell carcinomas (KSCC). HPV DNA, particularly type 16, was identified in 10 (100%) of 10 of NKCA and in only 2 (20%) of 10 of KSCC (P = .0014). NKCas were strongly reactive to p16 antibodies while KSCC showed weak and focal reactivity. Higher Ki67 and lower p53 staining scores were observed in NKCa as compared to KSCC. It is concluded that NKCa of the tonsils and base of tongue is a distinct subtype of squamous cell carcinoma of the head and neck with high prevalence of HPV DNA and a characteristic immunophenotype.

H3 and H3.3 histone mRNA amounts and ratio in oral squamous cell carcinoma and leukoplakia

Histone variants (e.g. H3) play an important role in chromatin structure and gene expression regulation of normal cells. Aims of this study were to: (1) estimate H3 and H3.3 histone mRNA expressions and their ratio in oral squamous cell carcinoma (OSCC) and oral leukoplakia (OL); (2) investigate whether H3 and H3.3 variants could play a role in the pathogenesis of OSCC and OL, also conditionally to HPV infection, age, gender, and main habits (tobacco smoking and alcohol drinking) in human beings studied. Twenty-three cases of OSCC and 20 cases of OL were examined in lesion site (LS) and juxtaposed clinically undamaged site (JUS) by RT-PCR for H3 and H3.3 histone mRNA; 13 healthy oral mucosa samples (HS) were investigated in a single site as controls. HPV DNA presence was investigated in the respective exfoliated oral mucosa cells by nested PCR (nPCR: MY09-MY11/GP5-GP6). The data showed that both H3 and H3.3 histone mRNA crude concentrations are higher in OSCC (LS = 2901 +/- 459 ng of H3; JUS = 2699 +/- 658 ng of H3; LS = 3190 +/- 411 ng of H3.3; JUS = 2596 +/- 755 ng of H3.3) than those in OL (LS = 2095 +/- 349 ng of H3; JUS = 2192 +/- 897 ng of H3; LS = 2076 +/- 911 ng of H3.3; JUS = 1880 +/- 654 ng of H3.3) and in HS (2579 +/- 959 ng of H3; 2300 +/- 758 ng of H3.3), although not reaching any statistical significance. Interestingly, ratio of H3/H3.3 mRNA amounts decrease both in OSCC (0.99) and OL (1.009) vs HS (1.121). No association was found for H3 and H3.3 histone mRNA expressions in OSCC and OL with respect to HPV infection and the social-demographical variables considered (P > 0.2). The overall higher expression of H3.3 in damaged tissues up to the ratio inversion in OSCC especially in HPV+ alcohol drinkers (60.0%) represents the most interesting finding, in consideration of the proven ability of alcohol to act as permeability enhancer of human oral mucosa, to alter the mucosal structure and by this dynamics could favour the penetration through the epithelial layers of HPV.

The impact of highly active antiretroviral therapy and immunodeficiency on human papillomavirus infection of the oral cavity of human immunodeficiency virus-seropositive adults

BACKGROUND

Prevalence of human papillomavirus (HPV)-associated oral condylomas has reportedly increased in HIV-infected individuals since the introduction of highly active antiretroviral therapy (HAART). The relationships between HIV therapy regimen, overall health, and subclinical oral HPV have not been examined.

GOAL

To determine oral HPV genotype prevalence and the impact of HAART and health in the HIV+ population.

STUDY

An L1 consensus-primer polymerase chain reaction and linear array assay were used to examine the prevalence of 27 HPV genotypes in saliva of 98 HIV+ individuals. Risk assessment variables were compared to oral HPV status.

RESULTS

Oral HPV was detected in 37% of HIV+ African American individuals. Caucasians were at greater risk of oral HPV infection than African Americans. Markers of advanced HIV disease did not predict HPV status. Therapy status was associated with HPV detection.

CONCLUSIONS

Treatment of HIV, rather than HIV immunosuppression, appears to play a role in oral HPV infections in HIV+ individuals.

HPV and other risk factors of oral cavity/oropharyngeal cancer in the Czech Republic

OBJECTIVE

An association between high-risk human papillomavirus (HR HPV) infection and a risk of development of a subgroup of head and neck cancers has been proposed recently. The main risk factors of oral and oropharyngal cancer observed in our population are smoking and alcohol consumption. The incidence of oral/oropharyngeal tumours in the Czech Republic is relatively high and there are no data available about the prevalence of HPV DNA presence in these tumours.

MATERIALS AND METHODS

Eighty patients with a primary oropharyngeal cancer were enrolled. The presence of HPV DNA has been evaluated by polymerase chain reaction in 68 cases from which the tumour tissue and demographical and clinical data were available. The typing of HPV was performed by nucleotide DNA sequencing.

RESULTS

The HPV DNA was detected in 51.5% of samples tested. Among the HPV DNA positive tumours, 80% contained HPV16. In the analysed group there were 54 men and 14 women. The prevalence of HPV DNA was lower in oral (25%) than in oropharyngeal (57%) tumours, and higher in never smokers (100%) and never drinkers (68.8%). HPV DNA presence was not related to gender, age, number of lifetime sexual partners or practice of oral-genital sex, size of tumour or presence of regional metastases.

CONCLUSIONS

The difference in the prevalence of HPV DNA positive tumours between cases of oral cavity and oropharyngeal carcinoma exposed and not exposed to tobacco or alcohol support the theory that HPV DNA positive tumours form an aetiologically distinct subgroup of head and neck tumours.

Antiviral activity of Cidofovir on a naturally human papillomavirus-16 infected squamous cell carcinoma of the head and neck (SCCHN) cell line improves radiation sensitivity

High risk HPV types 16 and 18 are associated with cervical cancer and squamous cell carcinoma of the head and neck (SCCHN). Cidofovir is an antiviral drug used to treat HPV-induced laryngeal papillomatosis and other viral infections, with initial reports suggesting activity in cervical carcinoma cells. We investigated the effects of Cidofovir on a naturally HPV-16-transformed SCCHN cell line (UPCI:SCC090), in comparison with a cervical carcinoma cell line (CasKi) of similar viral characteristics, to evaluate its therapeutic potential. HPV-16 gene transcription was only marginally reduced, and the antiviral and p53 restorative effects were modest in SCC90 cells. However, combination with irradiation enhanced the effects of Cidofovir treatment on these cells. Several days of treatment were required for this effect, which may limit its clinical applicability. Future therapies for HPV-associated tumors may include intralesional antiviral therapy in combination with radiation therapy, but optimization for clinical utility is needed.

Human papillomavirus status in advanced cervical cancer: predictive and prognostic significance for curative radiation treatment

Human papillomavirus (HPV) infection plays a major role in oncogenesis of squamous cell carcinoma of the cervix. This study was performed to investigate if HPV status and E2 gene integrity are prognostic parameters for clinical outcome and predictive for radiation response. Forty women with locally advanced cervical cancer treated with curative radiotherapy were analyzed for HPV infection and E2 gene integrity by multiplex polymerase chain reaction. Statistical analyses were performed for overall survival, disease-free survival (DFS), local progression-free survival, and treatment response (clinical complete remission). Twenty-eight (70%) of 40 carcinomas were HPV positive. The only significant factor for a better overall survival, DFS, and local progression-free survival was HPV positivity (P < 0.02, P= 0.02, and P < 0.05, log-rank, respectively). HPV-positive tumors had a significantly better clinical complete remission (67% vs 33%, P= 0.04, Fisher's exact test). An intact E2 gene region showed a trend for a better DFS (P= 0.1, log-rank). This study reveals HPV as an independent prognostic parameter for outcome and radiation response. Integration of the virus genome into host cell DNA might be a molecular target to determine the treatment response of HPV-positive cancers.

Human papillomaviruses in head and neck cancer: 8 year-survival-analysis of 73 patients

Depending on the primary tumour's anatomical location, squamous cell carcinoma of the head and neck (HNSCC) shows HPV prevalences between 20 and 30% for oro-, hypopharyngeal as well as laryngeal SCC and up to over 50% for SCC of the Waldeyer's tonsillar ring. There is persistent controversy on the role of HPV infection in HNSCC-progression, and on the influence of these infections on the final clinical outcome. To evaluate the possible relevance of HPV infection on survival and prognosis, 73 patients with HNSCC were investigated statistically with a median follow-up time of 28 (0.3-94) months. The statistical analysis revealed no differences in the overall survival of HPV-positive and HPV-negative cancer patients. A correlation between decreased survival and increased lymph node status was expected. Patients with carcinomas of the Waldeyer's tonsillar ring with a high HPV prevalence rate as compared to tumours of other anatomical locations revealed a better survival. Moreover, an association between HPV positivity and higher lymph node status at time of first diagnosis, and a better survival of HPV-positive patients compared to HPV-negative patients given the same initial nodal status (N0 vs. N1-N2b vs. N2c-N3) could be demonstrated. The influence of HPV on the patient's survival can only be observed statistically in combination with other prognostic factors, as the lymph nodal status of the patients. The better prognosis of survival of HPV-positive vs. the HPV-negative patients with lymph node neck metastasis is attributable to a better response of the HPV-positive group to therapy, especially radiotherapy.

Expression of cell cycle markers and human papillomavirus infection in oral squamous cell carcinoma: Use of fuzzy neural networks

Our aim was to evaluate in oral squamous cell carcinoma (OSCC) the relationship between some cell cycle markers and HPV infection, conditionally to age, gender and certain habits of patients, and to assess the ability of fuzzy neural networks (FNNs) in building up an adequate predictive model based on logic inference rules. Eighteen cases of OSCC were examined by immunohistochemistry for MIB-1, PCNA and survivin expression; presence of HPV DNA was investigated in exfoliated oral mucosa cells by nested PCR (nPCR, MY09-MY11/GP5-GP6), and HPV genotype was determined by direct DNA sequencing. Data were analyzed by traditional statistics (TS) and FNNs. HPV DNA was found in 9/18 OSCCs (50.0 %) without any significant higher risk of HPV infection with respect to the sociodemographic variables considered (p > 0.2), apart from tobacco smoking, reported in 44.4% of OSCC HPV-positive vs. 100% HPV-negative subjects (p = 0.029). Regarding cell cycle markers, TS and FNN revealed that survivin was expressed significantly more in HPV-negative than in HPV-positive OSCC [root mean-square error (RMSE) = 5.89 x 10(-6), % predicted 100.0]; furthermore, smoking played a protective role for survivin expression in HPV-positive cases (OR = 0.019, 95%CI 0.001-0.723, RMSE = 0.20, % of prevision 94.4). FNN, although on a small sample size, allowed us to confirm data by TS and to hypothesize a different cell cycle pattern for HPV-positive vs. HPV-negative OSCC. In the latter cases, the relevance of apoptotic vs. proliferative markers suggested that they may be related to the different supposed outcome of HPV-negative OSCC and that HPV may have a protective role in the expression level of survivin, especially in tobacco smokers.

Presence and Influence of Human Papillomaviruses (HPV) in Tonsillar Cancer

Tonsillar cancer is the most common of the oropharyngeal carcinomas and human papillomavirus (HPV) has been found to be present in approximately half of all cases. Patients with HPV-positive tonsillar cancer have been observed to have a better clinical outcome than patients with HPV-negative tonsillar cancer. Moreover, patients with tonsillar cancer and a high viral load have been shown to have a better clinical outcome, including increased survival, compared to patients with a lower HPV load in their tumors. Recent findings show that HPV-positive tumors are not more radiosensitive and do not have fewer chromosomal aberrations than HPV-negative tumors, although some chromosomal differences may exist between HPV-positive and -negative tonsillar tumors. Current experimental and clinical data indicate that an active antiviral cellular immune response may contribute to this better clinical outcome. These data are also in line with the findings that the frequency of tonsillar cancer is increased in patients with an impaired cellular immune system. Thus, therapeutic and preventive HPV-16 antiviral immune vaccination trials may be worthwhile, not only in cervical cancer, but also in tonsillar cancer.

Human papillomavirus-associated head and neck cancer is a distinct epidemiologic, clinical, and molecular entity

There is currently sufficient evidence to conclude that human papillomavirus (HPV) plays a role in the pathogenesis of a distinct subset of head and neck squamous cell cancers (HNSCC), particularly tonsillar cancers. There is a strong and consistent association between high-risk HPV types, specifically HPV16, a known human carcinogen, and these distinctive oropharyngeal cancers with molecular characteristics indicative of viral oncogene function. Risk for HPV-HNSCC is increased by certain sexual behaviors after consideration of alcohol and tobacco exposure, consistent with an extensive literature that has established HPV infection as a sexually transmitted disease. Furthermore, exposure to HPV16 has been associated with increased risk for subsequent development of oropharyngeal cancer. Prophylactic and therapeutic vaccines targeted against the viral capsid components and oncoproteins will provide the ultimate evidence for a role for HPV in HNSCC, if demonstrated to be effective in the prevention or therapy of this disease. It is time for clinician scientists to translate knowledge of this newly recognized disease entity into potential applications for the prevention, detection, and treatment of HPV-HNSCC.

Genetic patterns in head and neck cancers that contain or lack transcriptionally active human papillomavirus

BACKGROUND

Transcriptionally active high-risk human papilloma viruses (HPVs), particularly HPV type 16 (HPV16), are found in a subset of head and neck squamous-cell carcinomas (HNSCCs). HPV16-associated carcinogenesis is mediated by expression of the viral E6 and E7 oncoproteins, which cause deregulation of the cell cycle by inactivating p53 and pRb, respectively. We tested the hypothesis that HPV-associated HNSCCs display a pattern of genetic alterations different from those of HNSCCs without HPV DNA.

METHODS

Polymerase chain reaction-based assays were used to examine 143 consecutive HNSCCs (106 of the oral cavity and 37 of the oropharynx) for the presence of HPV DNA and for viral E6 and/or E7 messenger RNA (mRNA) expression. The HPV DNA-and E6 and E7 mRNA-positive HNSCCs and an equal number of HPV DNA-negative HNSCCs were further analyzed for mutations in TP53, the gene encoding p53, and for allelic loss of 28 microsatellite markers at chromosome arms 3p, 6q, 8p, 9p, 13q, 17p, and 18q, including markers located in regions of chromosome arms 9p and 17p that harbor genes involved the p53 and pRb pathways. All statistical tests were two-sided.

RESULTS

Twenty-four (16.7%) of the 143 HNSCCs were positive for HPV16 DNA, and 12 of these HNSCCs (8.4% of total number) expressed E6 and E7 mRNAs. None of the HPV DNA-and E6/E7 mRNA-positive tumors had TP53 gene mutations, whereas nine (75%) of the 12 HPV DNA-negative tumors had such mutations (P<.001). Compared with the HPV DNA-negative HNSCCs, the E6/E7 mRNA-positive HNSCCs had statistically significantly lower levels of allelic loss for 13 of the 15 markers on 3p, 9p, and 17p.

CONCLUSIONS

HNSCCs with transcriptionally active HPV16 DNA are characterized by occasional chromosomal loss, whereas HNSCCs lacking HPV DNA are characterized by gross deletions that involve whole or large parts of chromosomal arms and that already occur early in HNSCC development. These distinct patterns of genetic alterations suggest that HPV16 infection is an early event in HNSCC development.

The expression of key cell cycle markers and presence of human papillomavirus in squamous cell carcinoma of the tonsil

BACKGROUND

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.

METHODS

Fifty tonsil SCCs were analyzed for HPV by PCR and for expression of cell cycle proteins (p53, pRb, p16(INK4A), p21(CIP1/WAF1), p27(KIP1), and cyclinD1) by immunohistochemistry.

RESULTS

HPV was present in 42%; almost all were type 16. There were statistical associations between HPV positivity and reduced expression of pRb and cyclinD1, overexpression of p16, and younger patient age. Tumor with down-regulated p27 tended to have down-regulated pRb and p21.

CONCLUSIONS

HPV-positive tonsil SCCs have distinct molecular pathways. Their association with younger patient age suggests that they are biologically distinct from HPV-negative tumors.

Human papillomavirus, p53 and cyclin D1 expression in oropharyngeal carcinoma

Forty-two specimens from oropharyngeal (tonsil and base of tongue) squamous cell carcinoma patients (SCC) were studied for presence of HPV 16 by in situ hybridization and by immunohistochemistry for p53 and Cyclin D1 protein overexpression. Thirty-one per cent of cases were HPV-16 positive, which correlates with the prevalence reported worldwide. 74% of cases showed p53 protein overexpression and 79% showed Cyclin D1 overexpression. There was no correlation between HPV status and either p53 or Cyclin D1 overexpression (P>0.05). These three variables also did not correlate with factors such as grade of the tumour, stage of the disease or lymph nodal metastasis at presentation.

Epidemiological and clinical aspects of human papillomavirus detection in the prevention of cervical cancer

Cervical cancer is a major cause of death, and the second most frequent cancer in women worldwide. Many studies have indicated a causal relation between genital human papillomavirus (HPV) infections and cervical cancer. High-risk HPV genotypes have been detected in almost 100% of all cervical cancers, and the process of HPV mediated carcinogenesis has been partly clarified. The concept that HPV is a obligatory cause in cervical cancer development has lead to extensive research regarding the incorporation of HPV detection in (1) cervical cancer prevention programs, (2) triage of women with abnormal cervical scrapes in the screening program, and (3) follow-up of patients treated for cervical intraepithelial neoplasia (CIN). Epidemiological studies indicate that 50% of women becoming sexually active contract a genital HPV infection within 2 years. The lifetime risk of a genital HPV infection is estimated to be 80%, but very few of these women will develop cervical cancer. Several studies have shown that the persistence of genital HPV infections is especially related to the development of cervical cancer. As a result, HPV detection at a single moment was shown to be of limited clinical value in the triage of patients with abnormal cervical scrapes, or during follow-up after treatment for CIN. Furthermore, major variations in the sensitivity of different HPV detection methods, as well as differences in HPV detection related to the menstrual cycle, have shown that many facts regarding HPV transmission, replication, and detection need to be clarified, before HPV detection can be of clinical value.

Prevalence and clinical impact of Met Y1253D-activating point mutation in radiotherapy-treated squamous cell cancer of the oropharynx

Aberrant signalling through the hepatocyte growth factor/scatter factor receptor Met has been implicated in various aspects of the development of human cancer including the promotion of tumour invasion, angiogenesis and metastasis. Moreover, experimental data indicate that activation of the Met receptor may be involved in cellular resistance towards antineoplastic treatments such as chemotherapy and ionizing radiation. We determined the prevalence and clinical impact of the Met-activating mutation Y1253D in patients with squamous cell cancer of the oropharynx treated by radical radiotherapy. To screen archival tissue for the presence of a low-abundance point mutation, we developed a sensitive screening method using real-time polymerase chain reaction along with peptide nucleic acid-based DNA clamping and melting curve analysis. By this approach, Met Y1253D was detected in tumours of 15 out of 138 patients (10.9%). Both univariate and multivariate survival analysis revealed Met Y1253D to be significantly associated with impaired local tumour control. Our results provide evidence that the Met-activating mutation Y1253D is present in a notable subset of patients with oropharyngeal cancer and indicate that it may interfere with radioresponsiveness of these tumours, supporting the notion of aberrant Met signalling as a potential target for radiosensitization.

Prevalence of human papillomavirus type 16 DNA in squamous cell carcinoma of the palatine tonsil, and not the oral cavity, in young patients: a distinct clinicopathologic and molecular disease entity

Squamous cell carcinoma of the head and neck commonly affects patients in their sixth decade and older, particularly those with a prolonged history of alcohol and tobacco abuse. Less frequently, carcinomas occur in young individuals even in the absence of known risk factors. The purpose of this study is to investigate a possible relationship between these tumors and human papilloma virus (HPV). Thirty-three cases of squamous cell carcinoma of the head and neck in young patients under the age of 40 years were studied: 15 oral, 11 tonsillar, and 7 laryngeal. HPV DNA was detected by polymerase chain reaction in 10 tonsillar and 2 laryngeal carcinomas and in none of the oral tumors. Of the 12 HPV-positive tumors, 11 were HPV16 and 1 was HPV31. HPV-positive tumors had a distinct nonkeratinizing basal cell morphology, they stained diffusely and strongly with p16 antibodies, had higher Ki-67 and lower p53 staining scores as compared with the conventional keratinizing HPV negative carcinomas. It is concluded that in young patients high-risk HPV, particularly HPV16, is strongly associated with tonsillar squamous cell carcinoma and some cases of laryngeal, but not oral, tumors. The HPV-positive carcinomas have a distinct histopathologic and immunophenotypic features.

A subset of head and neck squamous cell carcinomas exhibits integration of HPV 16/18 DNA and overexpression of p16INK4A and p53 in the absence of mutations in p53 exons 5-8

Besides well-known risk factors such as tobacco use and alcohol consumption, oncogenic human papillomavirus (HPV) infection also has recently been suggested to promote head and neck tumorigenesis. HPV is known to cause cancer by inactivation of cell cycle regulators p53 and pRb via expression of viral oncoproteins E6 and E7. This indicates that p53 mutations are not a prerequisite in HPV-induced tumor development. However, discrepancy exists with respect to the frequency of head and neck squamous cell carcinomas (HNSCC) harboring DNA of oncogenic HPV and the fraction of these tumors showing p53 mutations. In our study, we examined the frequency of HNSCC demonstrating HPV 16/18 integration as identified by fluorescence in situ hybridization (FISH) and investigated their p53 (mutation) status by immunohistochemistry and single-strand conformation polymorphism (SSCP) analysis of exons 5-8. Paraffin-embedded, archival biopsy material from 27 premalignant mucosal lesions and 47 cases of HNSCC were analyzed. Ten of the 47 (21%) HNSCC unequivocally exhibited HPV 16 integration, including 8 of 12 (67%) tonsillar carcinomas. This is supported by the immunohistochemical detection of p16(INK4A) overexpression in all 10 HPV-positive tumors. Although FISH is considered to be less sensitive than PCR-based methods for HPV detection, our data clearly demonstrate clonal association of HPV with these tumors, as illustrated by the presence of integrated HPV 16 in both the primary tumor and their metastases in 2 patients. In contrast, HPV 16/18 DNA could not be detected in the premalignant lesions. In 30 of 47 (64%), HNSCC accumulation of p53 was observed, including 8 of the 10 HPV-positive carcinomas. However, in none of the latter cases could mutations in exons 5-8 be identified, except for a polymorphism in codon 213 of exon 6 in one patient. Evaluation of clinical data revealed a significant inverse relation between tobacco use with or without alcohol consumption, and HPV positivity of the tumors.

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, p21(CIP1/WAF1), pRb, p16(INK4A), cyclin D1 and p27(KIP1)) 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.

Human papillomavirus infection as a prognostic factor in carcinomas of the oral cavity and oropharynx

Although studies have established human papillomaviruses (HPVs) as a risk factor for oral and oropharyngeal cancer, it is not clear whether viral infection affects survival in head and neck malignancies. This investigation examined the relationship between HPV and survival in carcinomas of the oral cavity and oropharynx. Formalin-fixed, paraffin-embedded tumor specimens from 139 newly diagnosed cases were tested for HPVs by PCR and DNA sequencing. Patient and tumor characteristics were obtained from questionnaires, pathology reports and cancer registries. Odds ratios (ORs) and relative risks (RRs) were based on logistic and Cox regression models, respectively. HPVs were detected in 21% of the tumors; 83% were HPV-16. Greater risk of HPV infection was associated with males (OR = 2.9, 95% CI = 1.0-8.6), a history of oral-genital sex (OR = 4.2, 95% CI = 1.5-11.7), and oropharyngeal tumors (OR = 10.4, 95% CI = 3.5-31.2). As tobacco usage increased, the odds of HPV detection decreased (OR = 0.97/pack-year, 95% CI = 0.96-0.99). HPV infected patients had better overall survival (RR = 0.3, 95% CI = 0.1-0.8) than those with HPV-negative tumors. There was an interaction between gender and HPV for overall (p = 0.05) and disease-specific (p = 0.03) survival that suggested that HPV infected males had better prognosis than HPV-negative males, but this was not the case among females. HPV status was identified as an independent prognostic factor in oral and oropharyngeal cancers. This result appeared to be gender-specific, suggesting the need for further study of the interaction between HPV and gender on survival.

Reactivity to human papillomavirus type 16 L1 virus-like particles in sera from patients with genital cancer and patients with carcinomas at five different extragenital sites

A retrospective seroepidemiologic study was performed to examine the association between human papillomaviruses (HPV) 16 infection and carcinomas of the oropharynx, the oesophagus, penis and vagina. Sera were selected from the serum bank from the Antoni van Leeuwenhoek Hospital (Netherlands Cancer Institute) and the Slotervaart Hospital in Amsterdam, the Netherlands. Presence of HPV 16 specific antibody was assessed using HPV 16 L1 capsids. Sera positive for HPV 16 capsid antibody were further tested for antibody against HPV 16 E7 peptides. Prevalence of antibody against HPV 16 L1 capsids among both the negative control group without cancer and the negative control group with gastric cancer was 18%, while seroprevalence among the control group of patients with HPV-associated cervical squamous cell carcinoma was 47% (P<0.001). Among the patients with penile squamous cell carcinoma seroprevalence was 38% (P<0.001), among patients with oropharyngeal carcinoma 33% (P=0.04) and among patients with oesophageal squamous cell carcinoma 14% (P=0.7). The serological evidence for association between HPV 16 infection and both oropharyngeal carcinoma and penile carcinoma was established. The conclusion that no association was found between the presence of antibody against HPV 16 L1 capsids and oesophageal squamous cell carcinoma was in accordance with results of other studies carried out in the Netherlands using HPV DNA technology. In the subjects with HPV 16 L1 capsid antibody, no association was found between the antibody against HPV 16 E7 and clinical outcome.

Expression of p16 protein identifies a distinct entity of tonsillar carcinomas associated with human papillomavirus

Recent analyses of head and neck squamous cell carcinomas revealed frequent infections by oncogenic human papillomavirus (HPV) type 16 in tonsillar carcinomas. Concerning involvement of risk factors, clinical course of the disease, and prognosis there are strong indications arguing that the HPV-positive tonsillar carcinomas may represent a separate tumor entity. Looking for a surrogate marker, which in further epidemiological studies could replace the laborious and expensive HPV detection and typing we analyzed p16 protein expression in 34 tonsillar carcinoma for correlation to HPV status and load of viral DNA. p16 has been shown to be of diagnostic value for clinical evaluation of cervical dysplasia. We found 53% of the tested tonsillar carcinomas to be HPV-positive. Fifty-six percent of all tumors tested were immunohistochemically positive for the p16 protein. In 16 of 18 of the HPV-positive carcinomas diffuse p16 expression was observed. In contrast, only one of the HPV-negative carcinomas showed focal p16 staining (P < 0.001). As determined by laser-assisted microdissection and quantitative real-time polymerase chain reaction, p16 expression correlated with the presence of HPV-DNA in the individual tumor specimens. Clinical outcome analysis revealed significant correlation of p16 expression with increased disease-free survival (P = 0.02). These data indicate that p16 is a technically simple immunohistological marker, applicable for routine pathological histology, and its prognostic value for survival is fully equivalent to HPV-DNA detection.