High-risk human papillomavirus types and squamous cell carcinoma in patients with respiratory papillomas

HPV and Recurrent Respiratory Papillomatosis: A Brief Review

Recurrent Respiratory Papillomatosis (RRP) is a rare but severe manifestation of human papillomavirus (HPV). As our knowledge about HPV infections has expanded, it has become possible to understand the course of RRP disease and unravel plausible efficient methods to manage the disease. However, the surge in reports on HPV has not been accompanied by a similar increase in research about RRP specifically. In this paper, we review the clinical manifestation and typical presentation of the illness. In addition, the pathogenesis and progression of the disease are described. On the other hand, we discuss the types of treatments currently available and future treatment strategies. The role of vaccination in both the prevention and treatment of RRP will also be reviewed. We believe this review is essential to update the general knowledge on RRP with the latest information available to date to enhance our understanding of RRP and its management.

Assessment of HPV 16, HPV 18, p16 expression in advanced stage laryngeal cancer patients and prognostic significance

INTRODUCTION

Human papilloma virus is an etiological risk factor for a subset of head and neck squamous cell carcinomas. HPV has been proven to be a powerful prognostic biomarker for oropharyngeal cancer, but its role in the larynx has not been explored in depth. The developmental mechanisms of laryngeal carcinomas are quite complex and controlled by various factors. Smoking and alcohol are most important risk factors. Recent studies indicate that HPV infection also plays an important role in larynx carcinomas. HPV related laryngeal carcinomas especially occur at the supraglottic region of larynx.

OBJECTIVE

We aimed to determine the frequency of HPV/protein16 positivity in patients with laryngeal carcinoma and association of HPV and/or p16 positivity with variables such as age, sex, smoking habits, tumor localization, lymph node metastasis, recurrence and survival in advanced stage laryngeal carcinoma in our study.

METHODS

This retrospective study included 90 patients with advanced laryngeal carcinoma. The Control group was 10 normal larynx mucosa specimens. The presence of HPV was investigated polyclonally by polymerase chain reaction, and protein16 with immunohistochemical method. In HPV positive cases, the presence of HPV types 16, 18 were evaluated by polymerase chain reaction. Demographic features of patients were noted. Patient survival and association with HPV/protein16 was determined.

RESULTS

Polyclonal HPV positivity was detected in 11 (12.2%) of 90 cases. Out of these 11 cases, HPV 16 was positive in 6, HPV 18 in 4, and both HPV 16 and 18 were positive in 1. In 18 (20%) of the cases, p16 was positive. Six of the cases (6.6%) had both HPV and protein16 positivity. In cases where protein16 alone or HPV and protein16 were co-positive, alcohol use was less and the tumor was found more likely to be localized in the supraglottic area. These ratios were statistically significant. Supraglottic localization of tumor was determined to be increased in protein16 positive cases. The correlation between protein16 positivity and supraglottic area location was determined to be statistically significant (p =  0.011). 55.6% of protein16 positive cases was located in the supraglottic region, 33.3% was glottic and 11.1% was transglottic. Although life expectancy over 5 years were numerically higher in HPV and protein16 positive cases, this was not found to be statistically significant. There was no statistically significant relationship between HPV positivity and mean age, differentiation, smoking and alcohol use, tumor progression, lymph node metastasis, localization, recurrence, cause of mortality and treatment methods in our study. The mean follow-up period of our patients was 6.7 years.

CONCLUSION

The close relationship between HPV and oropharyngeal squamous cell carcinoma could not be shown in larynx malignancy in many studies, including our study. Our findings support a limited role of HPV in laryngeal carcinogenesis. Protein16 is not a reliable surrogate for HPV status in laryngeal cancers and is not a predictor of laryngeal cancer survival. Supraglottic localization of tumor was determined to be increased in protein16 positive cases. The correlation between protein16 positivity and supraglottic area location was determined to be statistically significant. There is a need for more populated clinical trials, where neoplastic proliferation is better demonstrated and the accuracy of the results obtained is supported by different techniques.

Immunological tolerance of low-risk HPV in recurrent respiratory papillomatosis

Recurrent respiratory papillomatosis (RRP) is characterized by benign exophytic lesions of the respiratory tract caused by the human papillomavirus (HPV), in particular low-risk HPV6 and HPV11. Aggressiveness varies greatly among patients. Surgical excision is the current standard of care for RRP, with adjuvant therapy used when surgery cannot control disease recurrence. Numerous adjuvant therapies have been used to control RRP with some success, but none are curative. Current literature supports a polarization of the adaptive immune response to a T helper type 2 (Th2)-like or T regulatory phenotype, driven by a complex interplay between innate immunity, adaptive immunity and HPV6/11 proteins. Additionally, certain immunogenetic polymorphisms can predispose individuals to an HPV6/11-tolerant microenvironment. As a result, immunomodulatory efforts are being made to restore the host immune system to a more balanced T cell phenotype and clear viral infection. Literature has shown exciting evidence for the role of HPV vaccination with Gardasil or Gardasil-9 as both primary prevention, by decreasing incidence through childhood vaccinations, and secondary prevention, by treating active RRP disease. Multi-institution randomized clinical trials are needed to better assess their efficacy as treatment for active disease. Interestingly, a DNA vaccine has recently shown in-vitro success in generating a more robust CD8⁺ T cell response. Furthermore, clinical trials for programmed death 1 (PD-1) inhibitors are under investigation for RRP management. Molecular insights into RRP, in particular the interplay between RRP and the immune system, are needed to advance our understanding of this disease and may lead to the identification of immunomodulatory agents to better manage RRP.

Multifocal Presentation of a Laryngeal Disorder

Multifocal presentation of a laryngeal disorder is very rare. We report a case of a 48-year-old man, who presented to our hospital with hoarse voice for two years. Stroboscopic evaluation followed by surgery was done and the specimens were sent for histopathological examination from three different anatomical sites of larynx which were diagnosed as one-benign lesion, second-benign lesion but ability of malignant transformation and the third-a malignancy.

Clinical course of recurrent respiratory papillomatosis: comparison between aggressiveness of human papillomavirus-6 and human papillomavirus-11

BACKGROUND

Recurrent respiratory papillomatosis (RRP) is mainly associated with human papillomavirus (HPV)6 or HPV11. The purpose of this study was to compare clinical outcome, aggressiveness, and treatment response between HPV6- and HPV11-associated RRP.

METHODS

A retrospective cohort of 55 patients with RRP (1974-2012) was used. Surgical interventions (n = 814) were analyzed, and complications scored. HPV6/11-specific polymerase chain reaction (PCR) was performed on RRP biopsies.

RESULTS

Seventy-six percent of patients (42 of 55) were infected with HPV6 and 24% (13 of 55) with HPV11. The HPV11 group had anatomically more widespread disease. The expected number of surgical interventions was higher in the younger age (<22.4 years) HPV11 group, and the older age (<22.4 years) HPV6 group. Regardless of HPV type, earlier age of onset of RRP resulted in a higher number of surgical interventions.

CONCLUSION

Anatomically, HPV11-associated RRP behaves more aggressively. Younger patients with HPV11 and older patients with HPV6 experience a worse clinical course of RRP.

Prevalence of diabetes mellitus and its impact on disease severity in adult recurrent respiratory papillomatosis

OBJECTIVES

Following human papilloma virus (HPV) infection, recurrent respiratory papillomatosis (RRP) develops secondary to dysfunction of innate and adaptive immune responses. Diabetes mellitus (DM) is a common medical disorder; these patients are considered to be relatively immunocompromised. It is hypothesized that comorbid DM occurs more frequently than expected in a cohort of adult RRP patients and that RRP patients with DM have more severe disease than those without DM.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary care laryngology practice, 5-year period.

SUBJECTS AND METHODS

Adult-onset RRP patients from 2007 to 2012 at the University of Washington were reviewed. The gender, age of onset of RRP, number of interventions, pathology, presence or absence of DM, and calculated anatomic Derkay severity score were recorded.

RESULTS

Eighty-four adult RRP patients were characterized; 64 male (76%) and 20 female (24%). Six of 84 patients (7.1%) had DM; this prevalence was not higher than an age-matched general population. The number of interventions required for disease control did not significantly differ (P = .13) between adult RRP patients with DM (avg 2.6/yr, median 2.3/year) and those without DM (avg 1.9/yr, median 1.3/yr). There was no significant difference in anatomic Derkay score at the time of intervention (P = .26) or presence of dysplasia in biopsy specimens (P = .49) between RRP patients with and without DM.

CONCLUSIONS

In this large series of adult RRP patients, DM does not appear to have a higher prevalence than that seen in age-matched controls, nor do RRP patients with DM appear to have more severe disease.

HPV associated with recurrent respiratory papillomatosis

Papillomaviruses are members of the Papillomaviridae family. Over 150 HPV types have been identified. Recurrent respiratory papillomatosis (RRP) is a chronic condition caused by HPV characterized by recurrent papillomas of the respiratory tract, mainly the larynx. During the early stages, the condition presents with hoarseness, while more advanced disease presents with stridor and respiratory distress. There is no specific cure and treatment consists of repeated surgical procedures to remove the papillomas. Most patients eventually go into remission, but some suffer for many years with this condition, which may be fatal. HPV-6 and HPV-11 are the HPV types most commonly associated with RRP. Although most studies have found RRP due to HPV-11 to be more aggressive than disease due to HPV-6, the variability in disease aggressiveness is probably multifactorial. Information regarding the current epidemiology, molecular diversity and host immune responses is important for strategizing ways to reduce disease. Data on HPV genotypes associated with RRP would provide valuable information for vaccination programs to reduce the incidence of these genotypes in mothers and, in the long term, reduce the incidence of RRP in children. This review focuses on HPV-6 and HPV-11 as the HPV types that cause RRP, and discusses the viral genome and replication, clinical presentation of RRP, current techniques of diagnosis and genotyping, and the molecular diversity of HPV-6 and HPV-11.

Detection and significance of human papillomavirus, CDKN2A(p16) and CDKN1A(p21) expression in squamous cell carcinoma of the larynx

Although a strong etiologic relationship between human papillomavirus (HPV) and a majority of oropharyngeal squamous cell carcinomas has been established, the role of HPV in non-oropharyngeal head and neck carcinomas is much less clear. Here, we investigated the prevalence and clinicopathologic significance of HPV and its reported biomarkers, CDKN2A(p16) and CDKN1A(p21), in laryngeal squamous cell carcinomas in patients treated either with primary surgery and postoperative radiation or with definitive radiation-based therapy. Nearly all of 76 tumors were keratinizing and none displayed the nonkeratinizing morphology that is typically associated with HPV infection in the oropharynx. However, CDKN2A(p16) immunohistochemistry was positive in 21 cases (28%) and CDKN1A(p21) in 34 (45%). CDKN2A(p16) and CDKN1A(p21) status strongly correlated with each other (P=0.0038). Yet, only four cases were HPV positive by DNA in situ hybridization or by reverse transcriptase PCR E6/E7 mRNA (all four were CDKN2A(p16) and CDKN1A(p21) positive). Unexpectedly, 9 additional tumors out of 20 CDKN2A(p16) positive cases harbored high-risk HPV DNA by PCR. For further investigation of this unexpected result, in situ hybridization for E6/E7 mRNA was performed on these nine cases and all were negative, confirming the absence of transcriptionally active virus. Patients with CDKN1A(p21)-positive tumors did have better overall survival (69% at 3 years) than those with CDKN1A(p21)-negative tumors (51% at 3 years) (P=0.045). There was also a strong trend towards better overall survival in the CDKN2A(p16)-positive group (P=0.058). Thus, it appears that the role of HPV is more complex in the larynx than in the oropharynx, and that CDKN2A(p16) and CDKN1A(p21) expression may not reflect HPV-driven tumors in most cases. Because of this, CDKN2A(p16) should not be used as a definitive surrogate marker of HPV-driven tumors in the larynx.

Delineating an epigenetic continuum in head and neck cancer

A tissue field of somatic genetic alterations precedes the histopathological phenotypic changes of carcinoma. Genomic changes could be of potential use in the diagnosis and prognosis of pre-invasive squamous head and neck carcinoma (HNSCC) lesions and as markers for cancer risk assessment. Studies of sequential molecular alterations and genetic progression of pre-invasive HNSCC have not been clearly defined. Studies have shown recurring alterations at chromosome 9p21 (location of the CDKN2A) and TP53 mutations in the early stages of HNSCC. However, gene silencing via hypermethylation is still a relatively new idea in the development of HNSCC and little is known about the contribution of epigenetics to the development of neoplasia, its transformation, progression, and recurrence in HNSCC. This review examines the role of promoter hypermethylation of tumor suppressor genes in the progression continuum from benign papillomas to malignancy in HNSCC.

Novel human papilloma virus (HPV) genotypes in children with recurrent respiratory papillomatosis

INTRODUCTION

Recurrent respiratory papillomatosis (RRP) is characterized by the presence of benign virally induced tumors of the larynx and respiratory epithelium that may obstruct the airway and tend to recur frequently. RRP is caused by the human papilloma virus (HPV), most frequently by HPV types 6 and 11. In this study, we present four cases of children with RRP in whom HPVs other than HPV-6 or HPV-11 were found.

MATERIAL AND METHODS

In all four cases, HPV typing was performed by polymerase chain reaction (PCR) followed by restriction digestion (RFLP) in biopsy samples collected during surgery.

RESULTS

In the first case, simultaneous HPV infection with types 13 and 39 was detected, while in the second case HPV-40 and HPV-56 were found. In cases 3 and 4, the biopsy samples were positive for unidentified 'low-risk' HPVs.

CONCLUSIONS

The presence of novel HPV genotypes in children with RRP emphasizes the need for further investigation of the implication of these genotypes in the disease.

Consistent DNA hypermethylation patterns in laryngeal papillomas

INTRODUCTION: This study examined the contribution of promoter hypermethylation to the pathogenesis of respiratory papillomatosis (RP), including recurrences (RRP) and progression to squamous cell carcinoma (SSC). MATERIALS AND METHODS: A retrospective cohort of 25 laryngeal papilloma cases included 21 RRP, two of which progressed to SCC. Aberrant methylation status was determined using the multi-gene (22 tumor suppressor genes) methylation-specific multiplex ligation-dependent probe amplification assay and confirmed using methylation specific PCR. RESULTS: Twenty genes had altered DNA methylation in 22 of 25 cases. Aberrant methylation of CDKN2B and TIMP3 was most frequent. Promoter hypermethylation of BRCA2, APC, CDKN2A and CDKN2B was detected in 2 RRP cases with subsequent progression to SCC. Of the 25 cases, 22 were positive for HPV-6, 2 for HPV-11 and 1 for HPV-16 and 33. CONCLUSIONS: Consistent aberrant methylation of multiple tumor suppressor genes contributes to the pathogenesis of laryngeal papillomas. Persistent aberrant DNA methylation events in 2 RRP cases that progressed to cancer indicate an epigenetic monoclonal progression continuum to SCC.

Comparison of human papillomavirus detection and typing by hybrid capture 2, linear array, DNA chip, and cycle sequencing in cervical swab samples

Although the Hybrid Capture II (HC II) assay can detect 13 high-risk human papillomavirus (HPVs), it does not yield any genotype-specific information. We evaluated the performance of 4 HPV DNA tests, namely, HC II, Linear Array (LA), DNA chip, and cycle sequencing for their capacity to detect the presence of high-risk HPV DNA and HPV-associated cervical lesions. Seventy-six women who were referred to the colposcopy clinic for abnormal cytology were enrolled. The women were examined using liquid-based cytology, colposcopy-directed biopsy, and HPV DNA tests. After DNA extraction from a single sample, HPV DNA tests were performed by all 4 methods on the same specimen. The LA test has higher HPV-positive rates than HC II for cervical intraepithelial neoplasia I (83.3% vs 61.1%; P < 0.01) and for cervical intraepithelial neoplasia II and more severe lesions (100.0% vs 80.0%; P < 0.01). The concordance between the DNA chip and LA tests was 89.5%, confirming substantial agreement (kappa coefficient = 0.73), and the concordance between HC II and the DNA chip was 80.3%, also showing substantial agreement (kappa coefficient = 0.738). The concordance for 15 high-risk HPV genotypes between LA and sequencing was 82.5% with a kappa value of 0.536. Furthermore, the LA test was more sensitive in the detection of high-grade cervical lesions than HC II (100% vs 92.3%, P < 0.01). The LA test showed superior sensitivity in the detection of clinically relevant HPV infections and has proven to be an accurate tool for identifying individual HPV types, especially in cases of multiple HPV infections.

Recurrent Respiratory Papillomatosis: A Longitudinal Study Comparing Severity Associated With Human Papilloma Viral Types 6 and 11 and Other Risk Factors in a Large Pediatric Population

OBJECTIVES/HYPOTHESIS

A database was developed for prospective, longitudinal study of recurrent respiratory papillomatosis (RRP) in a large population of pediatric patients. Data recorded for each patient included epidemiological factors, human papilloma virus (HPV) type, clinical course, staged severity of disease at each surgical intervention, and frequency of surgical intervention. The study hypothesizes that patients with HPV type 11 (HPV-11) and patients younger than 3 years of age at diagnosis are at risk for more aggressive and extensive disease.

STUDY DESIGN

The 10-year prospective epidemiological study used disease staging for each patient with an original scoring system. Severity scores were updated at each surgical procedure.

METHODS

Parents of children with RRP referred to the authors' hospital completed a detailed epidemiological questionnaire at the initial visit or at the first return visit after the study began. At the first endoscopic debridement after study enrollment, tissue was obtained and submitted for HPV typing using polymerase chain reaction techniques and in situ hybridization. Staging of disease severity was performed in real time at each endoscopic procedure using an RRP scoring system developed by one of the authors (B.J.W.). The frequency of endoscopic operative debridement was recorded for each patient. Information in the database was analyzed to identify statistically significant relationships between extent of disease and/or HPV type, patient age at diagnosis, and selected epidemiological factors.

RESULTS

The study may represent the first longitudinal prospective analysis of a large pediatric RRP population. Fifty-eight of the 73 patients in the study underwent HPV typing. Patients infected with HPV-11 were significantly more likely to have higher severity scores, require more frequent surgical intervention, and require adjuvant therapy to control disease progression. In addition, patients with HPV-11 RRP were significantly more likely to develop tracheal disease, to require tracheotomy, and to develop pulmonary disease. Patients receiving a diagnosis of RRP before 3 years of age had significantly higher severity scores, higher frequencies of surgical intervention, and greater likelihood of requiring adjuvant medical therapy. Patients with Medicaid insurance had significantly higher severity scores and required more frequent surgical debridement. Birth by cesarean section appeared to be a significant risk factor for more severe disease and necessity of more frequent surgical intervention.

CONCLUSION

Statistical analysis of the relationships among epidemiological factors, HPV type, and clinical course revealed that patients with HPV-11 and patients younger than 3 years of age at RRP diagnosis are prone to develop more aggressive disease as represented by higher severity scores at endoscopic debridement, more frequent operative debridement procedures per year, a greater requirement for adjuvant therapy, and greater likelihood of tracheal disease with tracheotomy.

Side-effects of cidofovir in the treatment of recurrent respiratory papillomatosis

Recurrent respiratory papillomatosis (RRP) is a chronic and difficult to treat disease of the larynx. In 1998, the first article was published that described the use of the antiviral substance cidofovir to treat this disease. Although the results are promising, there remains some concern about the potential carcinogenicity of cidofovir. There is a demand for a qualitative review of the side-effects of this medicine. In this review, the side-effects of cidofovir are investigated. Special attention was given to the potential carcinogenicity of cidofovir. For this review a search is performed in PubMed and EMBASE for relevant articles in which the use of intralesional cidofovir for patients with RRP is described. Eventually, 31 articles could be included for this review. In these articles a total of 188 patients with RRP were described who underwent therapy with intralesional cidofovir. Five of these patients have developed dysplasia of the larynx during the treatment with cidofovir. This is a percentage of 2.7. This percentage is concurrent with the incidence of spontaneous malignant degeneration of RRP (2–3%). Based on this review, it can be concluded that the use of intralesional cidofovir does not increase the risk of laryngeal dysplasia. Apart from the articles that describe the intralesional administration of cidofovir, some articles have been published in which the use of intravenous cidofovir is described as a therapy for RRP. Therefore, a summary is given on the side-effects of intralesional cidofovir as well as a summary on the reported side-effects of the intravenous administration of cidofovir. Based on the outcomes of this review, recommendations are given for a safe use of cidofovir for treatment of recurrent respiratory papillomatosis in the future.

Lung involvement in juvenile onset recurrent respiratory papillomatosis: a systematic review of the literature

OBJECTIVES

Determine the exact incidence of pulmonary involvement in recurrent respiratory papillomatosis (RRP); explore available treatments and their effectiveness; determine the characteristics of cases that progress to lung cancer.

DATA SOURCES

MEDLINE, EMBASE, and the Cochrane Library databases between 1966 and 2007; reference lists of retrieved publication.

STUDY SELECTION

Studies investigating recurrent respiratory papillomatosis with lung involvement. Age limited to 20 years of age to qualify for the diagnosis of juvenile-onset RRP.

DATA EXTRACTION

Data pertaining to study design, population demographics, risk factors, site of involvement, investigation including the determination of the human papillomavirus type, treatment, and outcomes including the development of cancer.

DATA SYNTHESIS

No randomized control trials were retrieved. Hundred and one studies met our inclusion criteria (23 cohorts, 4 case series, 72 case reports, 2 open trials) with 161 cases of lung involvement identified. From the cohort studies we could estimate the incidence of lung involvement in RRP at 3.3%. The incidence of cancer in cases with lung involvement was 16%. We could not draw conclusions regarding treatment effectiveness in lung involvement, as that was not evaluated except in case studies. It would nevertheless appear that Interferon is not effective and the use of intravenous Cidofovir needs to be better evaluated.

CONCLUSION

Well-designed, hypothesis-driven randomized control trials and prospective cohort studies are warranted to improve our understanding of the mechanisms underlying the development of lung involvement in RRP, the risks associated with different HPV types, the efficacy of potential therapeutic options as well as the risk of progression to cancer.

Laryngeal carcinoma in a non-smoker female patient with thyroid carcinoma: report of a case

Laryngeal carcinoma is usually encountered in smoker men, and thyroid carcinoma is sometimes discovered incidentally during treatment for these patients. However, this coexistence of malignancies could occur in non-smoker female. We report an unusual case of multiple primary malignancies in the larynx and the thyroid gland. The laryngeal carcinoma was suspected to be related to the malignant transformation of the papillomas. The case suggests the importance of meticulous examination in the head and neck region for treatment of cervical metastatic lymph nodes with negative cytology in non-smoker female.

Detection of human papillomavirus and relevant tumor suppressors and oncoproteins in laryngeal tumors

PURPOSE

The mechanism of larynx oncogenesis is complex and controlled by various factors, most of them involved in cell proliferation and apoptosis. In this study, we evaluated the levels of two suppressor proteins (pRb and p53) and two oncogenic proteins (c-Myc and Bcl-2), as well as the apoptotic levels and the presence of human papillomavirus (HPV) in both tumor types.

EXPERIMENTAL DESIGN

Low- or high-risk HPV viral DNA was determined by PCR and in situ PCR; the level of cellular proteins was examined by immunohistochemistry; the presence of apoptotic cells was evaluated by in situ cell death detection.

RESULTS

Most laryngeal papillomatosis samples contained low-risk HPV determined by both techniques. However, 25% of laryngeal carcinoma samples were positive for HPV employing PCR or in situ PCR. In papillomatosis, pRb and p53 levels were higher than in normal larynxes, whereas laryngeal cancer presented the lowest levels. c-Myc oncogene expression was very low in normal and cancer tissues but highly increased in papillomatosis. Bcl-2 expression was low and showed no significant difference between laryngeal papillomatosis and normal larynxes. By contrast, Bcl-2 was clearly up-regulated in cancer. Normal larynx samples and those from laryngeal papillomatosis exhibited similar relatively high numbers of apoptotic cells, whereas in malignant tumors, these cells were scarce.

CONCLUSION

Our results suggest that HPV is an important risk factor in papillomatosis and in some malignant larynx tumors with a strong participation of cellular genes, specifically involved in proliferation and apoptosis. In benign papillomatosis lesions but not in larynx cancer, high p53 activity might preserve the apoptosis process. In larynx cancer, low p53 levels and high bcl-2 expression may be playing an important role to block apoptosis.

Intralesional Cidofovir application in recurrent laryngeal papillomatosis

Recurrent laryngeal papillomatosis is a benign disease of the larynx often leading to organic and functional restrictions. The therapeutic treatment of choice in larynx-obstructing papillomatosis is at present surgical laser ablation. The effectiveness of adjuvant intralesional injection of the virustaticum Cidofovir has been investigated recently in a variety of therapeutic models. The present case study deals with the treatment of recurrent laryngeal papillomatosis by means of surgical laser ablation of the laryngeal papillomas with adjuvant local injection of the virustaticum Cidofovir (dose of 5 mg/1 ml). Within the period from October 2001 to August 2004, ten patients aged between 5- and 70 years were treated with intralesional injections of Cidofovir. Papillomatosis was confirmed histologically in all cases, and the virus types were defined in part. Each of the patients underwent clinical-phoniatric examinations and was photographed for documentation. After 2-7 treatments with surgical laser papilloma ablation and intralesional Cidofovir injections, all patients showed a definite papilloma reduction, while in six cases complete remission was achieved. During the follow-up period of 8-30 months, not a single recurrence of the laryngeal papillomatosis occurred. In the majority of patients, a clear improvement in the voice was achieved. There were no local or systemic side effects caused by the virustaticum. Intralesional injection of Cidofovir is an adjuvant, but not a curative therapeutic option in recurrent laryngeal papillomatosis. Remission of previously frequently recurrent laryngeal papillomas can be achieved, but recurrence after longer treatment-free intervals is also possible.

Human Papillomavirus Infections of the Genital and Respiratory Tracts in Young Children

Human papillomavirus (HPV) causes papillomas (warts) on the skin and respiratory mucosal surfaces (laryngeal and oral papillomas) in addition to condyloma acuminata (anogenital warts). HPV has become one of the most common sexually transmitted diseases in adults. Vertical transmission from mother to infant during birth is well recognized. Laryngeal papillomas are the most common tumors of the larynx in children worldwide, and recurrent lesions are common occurrences. Anogenital warts in children are problematic in that child sexual abuse is a potential means of acquisition, but many cases are acquired perinatally. Postnatal acquisition by nonsexual means also can occur. The likelihood of sexual abuse as the mode of acquisition increases with increasing age in childhood. The virus infects primarily epithelial cells, where it can exist as a long-term latent infection that can reactivate or persist actively (even subclinically), with resultant accumulation of host chromosomal mutations. The latter accounts for the oncogenic potential of a number of HPV types, and childhood infections may lead to neoplasia later in life. Regression of papillomas over the course of months to years is the usual natural course. Numerous treatments are available, but most do not prevent persistent infection or problematic recurrences. Multivalent HPV vaccines have been developed, and early results of clinical trials appear to be very promising.

Integration of human papillomavirus type 11 in recurrent respiratory papilloma-associated cancer

OBJECTIVES/HYPOTHESIS

The main objective was to demonstrate that human papillomavirus (HPV) type 11 is an aggressive virus that plays a significant role in the development of laryngeal cancer in patients with a history of recurrent respiratory papillomatosis (RRP). We have done so by preliminary investigation into the molecular mechanism underlying the malignant transformation of RRP to invasive squamous cell carcinoma.

STUDY DESIGN

An experimental, nonrandomized, retrospective study using tissue specimens from nine patients with a history of RRP that progressed to laryngeal or bronchogenic cancer was performed.

METHODS

DNA and RNA were extracted from 20 formalin-fixed, paraffin-embedded specimens from six patients with a history of early onset RRP and laryngeal cancer and from three patients with early onset RRP and bronchogenic cancer. Polymerase chain reaction (PCR) was performed on DNA to determine the HPV type in each specimen. Reverse-transcriptase PCR specific for virus transcripts was performed on RNA to determine whether the viral genome was integrated into the host genome.

RESULTS

HPV-11 but not HPV-6, 16, or 18 was found in all of the laryngeal and bronchogenic cancers in patients with a history of early onset RRP in this study. RNA, sufficiently intact for examination, was obtained from seven patients. Analysis of HPV 11 transcripts revealed integration of the viral genome in three of seven patients.

CONCLUSIONS

HPV type 6 and 11 are considered "low-risk" viruses and are not associated with genital cancers, as are HPV types 16 and 18. However, our data suggests that HPV type 11 is an aggressive virus in laryngeal papilloma that should be monitored in patients with RRP.

Overview of recurrent respiratory papillomatosis

PURPOSE OF REVIEW

The purpose of this article is to review recent literature regarding pediatric recurrent respiratory papillomatosis (RRP) published within the last year. By reviewing and assessing these articles, a more clear understanding regarding the etiology and management of pediatric RRP can be obtained, allowing physicians to better care for their pediatric RRP patients.

RECENT FINDINGS

Pediatric RRP continues to be an extremely difficult management problem for otolaryngologists. This disease process continues to be a significant burden on the health care system and is a significant cause of morbidity in affected patients and their families. The incidence of RRP continues to be approximately 3.96 per 100,000 in the pediatric population. It has been noted recently that approximately 7 of every 1000 children born to mothers with vaginal condyloma develop pediatric RRP. Although the mainstay of surgical management has traditionally been the CO2 laser, newer surgical techniques have demonstrated efficacy in the management of pediatric RRP patients, including powered instrumentation and the pulse-dye laser. The traditional adjuvant medical therapies used for pediatric RRP continue to be commonly used, including interferon-alpha2a, retinoic acid, and indol-3-carbinol/diindolylmethane (I3C/DIM). Recently cidofovir has demonstrated efficacy in selected patients. In addition, current research regarding vaccine therapy for pediatric RRP has shown promise. Basic science research in the field of immunology has demonstrated multiple defects in cell-mediated immunity, which has shed further light on the etiology of pediatric RRP.

SUMMARY

Pediatric RRP continues to be a highly morbid disease process. New surgical and medical therapies offer hope for better control of this disease in affected patients. Recent advances in immunologic research offer the hope of immune system modulation and augmentation as potential future treatment modalities to better control this disease process.

Propagation of infectious human papillomavirus type 16 by using an adenovirus and Cre/LoxP mechanism

Human papillomavirus type 16 (HPV16) infection is a major risk factor for the development of squamous cell cancers of the cervix and of the head and neck. A major barrier to understanding the progression from initial infection to cancer has been the lack of in vitro models that allow infection, replication, and persistence of the viral genome as an episome in differentiated epithelial cells. To overcome this barrier, we designed an adenoviral delivery vector that contained a full HPV16 genome flanked by LoxP homologous recombination sites and a fluorescent reporter that was expressed only after the HPV genome was excised by Cre recombinase. This system delivered circular HPV16 genomes to cervical epithelial cells and well differentiated human airway epithelia. After delivery, the HPV16 genome replicated and persisted as an episome in cervical keratinocytes. These cells developed an immortalized phenotype and a dysplastic epithelial appearance. Moreover, induction of differentiation led to the expression of late genes and production of infectious HPV16 virions. This work provides a means of introducing biologically active HPV genomes into epithelial cells, which are normally difficult to transfect. These methods allow the study of HPV genome replication and gene expression in the earliest stages of HPV genome establishment, and they may provide a means to study nononcogenic HPV viral types.

Human papillomavirus testing methods

Testing for human papillomavirus (HPV) relies exclusively on techniques of molecular biology using nucleic acid probes. Tests for HPV using nucleic acid probes have been commercially available since the late 1980s, but early tests were cumbersome, involving the use of nucleic acid probes labeled with radioactive phosphorus (32P). These early HPV tests did not achieve widespread use because they did not detect all oncogenic HPV genotypes. The current commercial HPV detection kit, Digene's Hybrid Capture 2 kit, detects virtually all high-risk oncogenic HPV types, as well as most low-risk nononcogenic HPV genotypes. The Hybrid Capture 2 test format is a proprietary nucleic acid hybridization signal amplification system owned by Digene Corporation. Virtually all test formats for DNA sequence analysis are amenable to applications intended to detect and perhaps quantify the various HPV genotypes. These methods can involve direct hybridization with complementary DNA probes, such as Southern blotting or in situ hybridization, signal amplification, such as the Hybrid Capture 2 method or target nucleic acid amplification, most notably the polymerase chain reaction (PCR). Polymerase chain reaction has been used for HPV detection, genotyping, and viral load determination. General or consensus primer-mediated PCR assays have enabled screening for a broad spectrum of HPV types in clinical specimens using a single PCR reaction. Following amplification using consensus primers, individual HPV genotypes are identified using a variety of methods. Using consensus primers in a test format known as real-time quantitative PCR (RQ-PCR), it is possible to generate viral load (concentration) data from reaction curves generated by monitoring PCR reaction kinetics in real time.

Infectious human papillomavirus type 31b: purification and infection of an immortalized human keratinocyte cell line

Human papillomaviruses (HPVs) are aetiological agents of human malignancies, most notably cervical cancers. The life-cycles of HPVs are dependent on epithelial differentiation, and this has impeded many basic studies of HPV biology. The organotypic (raft) culture system supports epithelial differentiation such that infectious virions are synthesized in raft tissues from epithelial cells that replicate extrachromosomal HPV genomes. The CIN-612 9E cell line maintains episomal copies of HPV type 31b (HPV31b), an HPV type associated with cervical cancers. Many previous studies, including our own, have focused on characterizing the later stages of the HPV31b life-cycle in CIN-612 9E raft tissues. In this study, we have used the raft system to generate large numbers of HPV31b viral DNA (vDNA)-containing particles. We found a biologically contained homogenization system to be efficient at virion extraction from raft epithelial tissues. We also determined that vDNA-containing particles could be directly quantified from density-gradient fractions. Using an RT-PCR assay, the presence of newly synthesized, spliced HPV31b transcripts was detected following HPV31b infection of the immortalized HaCaT epithelial cell line. Spliced E6 and E1( wedge )E4 RNAs were detected using a single round of RT-PCR from cells infected with a dose as low as 1.0 vDNA-containing particle per cell. Spliced E1*I,E2 transcripts were found in cells infected with an HPV31b dose as low as 10 vDNA-containing particles per cell. Infectivity was blocked by HPV31 antiserum, but was not affected by DNase I. This work lays a foundation for a detailed analysis of the early events in HPV infection.

Molecular Events in the Progression of Recurrent Respiratory Papillomatosis to Carcinoma

Context.—Identification of the type of human papillomavirus (HPV) by polymerase chain reaction and sequencing to determine coinfection or superinfection (by more than 1 HPV type) and other molecular events have not been reported in a series of patients exhibiting the morphologic spectrum of recurrent respiratory papillomatosis progressing to carcinoma.

Design.—Four cases of juvenile-onset recurrent respiratory papillomatosis progressing to carcinoma (no history of smoking or irradiation in 2 cases) were studied. Morphologically distinct foci (squamous papilloma, pulmonary papillomatosis, squamous dysplasia subjacent to carcinoma, and squamous carcinoma) were subjected to laser capture microdissection and polymerase chain reaction amplification using general primers in addition to type-specific primers for HPV types 16 and 18. Direct sequencing of polymerase chain reaction products identified the type of HPV. The tissue sections were immunostained using antibodies to p53, pRb, p21WAF1, and p16 proteins with a semiquantitative assessment.

Results.—Human papillomavirus 11 was the only type of HPV identified in all lesions of all cases associated with recurrent respiratory papillomatosis. There was a marked increase in p53 protein expression in foci of dysplasia and carcinoma as compared to squamous papilloma and pulmonary papillomatosis. An inverse correlation between p53 and p21WAF1 protein expression was noted in all lesions. pRb protein expression increased from the benign to the malignant end of the spectrum. p16 protein was expressed in all lesions.

Conclusions.—Infection by HPV-11 may be an early event associated with progression of recurrent respiratory papillomatosis to carcinoma. Increased expression of p53 and pRb proteins and a reduced expression of p21WAF1 protein appear to be significant subsequent events.

CO(2) laser treatment in 244 patients with respiratory papillomas

OBJECTIVE

Respiratory papillomas (RP) tend to recur and the difficulty in eradicating the disease makes their treatment frustrating. Meticulous CO(2) laser excisions every 2 months has been the most effective treatment to date. This article analyzes the results of this plan in 244 patients with RP in the nose, nasopharynx, pharynx, hypopharynx, larynx, trachea, lung parenchyma, and skin.

METHODS

Two hundred forty-four patients with recurrent RP were treated by the senior author with CO(2) laser excisions and, in some cases, podophyllum and alpha interferon. Demographics, initial distribution of papillomas, number of operations performed on each patient, and current results were evaluated.

RESULTS

Careful laser excisions of RPs every 2 months achieved "remission" of disease (no visible RP on indirect or often direct laryngoscopy 2 mo after last removal) in 37% of patients, "clearance" of the disease process (no RP clinically apparent for 3 y after last removal) in 6%, and "cure" (no clinical recurrence for 5 y after last removal) in 17%. Juvenile-onset RP tends to follow a more aggressive course than adult-onset RP. Four patients (1.6%) developed malignant transformation of their papillomas. Except for ones in lung parenchyma, RP in areas other than the true vocal cords tend to be cleared faster because aggressive removal does not cause hoarseness. Lung parenchyma RPs are eventually fatal because of pulmonary failure from abscesses and cysts resulting from a lack of effective treatment.

CONCLUSION

Frequent and meticulously performed CO(2) laser excisions can achieve significant voice and airway improvement, and some clinical "cures." However, effective antiviral medicines and/or immunologic agents are needed to achieve true cures with elimination of all human papilloma virus 6 and 11 viruses.

Detection of human papillomavirus gene sequences in cell lines derived from laryngeal tumors

The role of Human Papillomaviruses (HPV) in laryngeal carcinomas has been studied with conflicting results. To evaluate the etiologic relationship between HPV infection and epithelial malignancy of the larynx we studied five laryngeal carcinoma cell lines obtained from patients undergoing surgery for laryngeal tumors. The paraffin embedded biopsy samples of the original tumor and different passages of the new established cell lines were investigated by PCR with consensus primers specific for HPV DNA. The findings indicate that HPV infection is associated with some larynx carcinomas. The positive association has been enhanced when a method of enrichment of epithelial cells from fresh tumor samples was used. All tumor cells enriched smears were positive for HPV DNA not only by PCR but also by in situ hybridization (ISH). Investigated by PCR, different passages of larynx tumor cell lines maintained expression of HPV DNA. At subsequent passages ISH gives constantly no signals suggesting a minimal amount of viral harbored sequences. In one cell line propagated more than 60 population doublings, the chromosomal frequency distribution shifted from modal number 46 at the 5(th) passage to 63 at the 60(th) passage. The mechanisms by which persistent HPV infection maintains continuous cell proliferation were discussed.