Laryngeal dysplasia and the human papillomavirus

Etiologia do Carcinoma Epidermóide de Hipofaringe

A carcinogênese é uma alteração do controle do crescimento celular devido a uma exposição prolongada a algum agente com potencial mutagênico. O tabagismo é um importante determinante do risco de câncer de faringe, e a associação com o etilismo aumenta ainda mais este risco. Fatores nutricionais, como na síndrome de Plummer-Vinson, em que há uma anemia ferropriva, parecem ter também importância. Como apenas uma fração dos indivíduos expostos a tabagismo e etilismo desenvolvem câncer, sugere-se que fatores específicos do hospedeiro estabeleçam suscetibilidade diferente. Assim, o sexo masculino é o mais acometido, bem como a sexta e sétima décadas. Encontrou-se um risco relativo maior com a exposição a certas substâncias. Portadores de um primeiro tumor, exposição a radioterapia prévia e aos vírus da papilomatose humana (HPV) e, menos freqüentemente, EBV, apresentam maior risco de desenvolvimento de um câncer faríngeo. Parece ainda haver uma predisposição familiar, bem como uma correlação com a ativação de oncogens e a inativação de gens supressores de tumores, como o p53.

HPV in Head and Neck Cancer-30 Years of History

The interesting history of papillomavirus (PV) research has been reviewed before. The history of human papillomavirus (HPV) in head and neck region starts in 1901 when the contagious transmission of warty lesions into the mouth via oral sex was described, although the confirmation of their viral etiology had to wait until 1907. Ullman was the first to associate the human wart virus with laryngeal warts. Parsons and Kidd described the natural history of oral PV infections in rabbits already in 1942, but these findings were corroborated in humans only recently. Koilocytotic atypia described by Koss and Durfee in 1956 was recognized as a sign of HPV infection in cervical precancer lesions only in 1976-1977 (Meisels and Fortin; Purola and Savia). This prompted systematic surveys of head and neck lesions for the detection of koilocytosis since the late 1970s, and the authors of this communication were the first to propose the HPV involvement in a subgroup of head and neck cancers. Brandsma and Abramson demonstrated HPV16 DNA in tonsillar SCCs in 1989. Since the early 2000s, HPV research of head and neck squamous cell carcinomas (HNSCC) has made impressive progress, confirming that the specific anatomic site plays a key role in determining the susceptibility to HPV infection. The most likely cancer sites associated with HPV are the base of the tongue and palatine tonsils, followed by oral cavity, larynx, and sinonasal mucosa. There is substantial geographic variation in HPV association with HNSCC. Patients with HPV-associated HNSCC are younger, and survival is better than in the absence of HPV.

Laryngeal Squamous Intraepithelial Lesions: An Updated Review on Etiology, Classification, Molecular Changes, and Treatment

Laryngeal carcinogenesis is a multistep process, characterized by an accumulation of genetic changes associated with architectural and cytologic alterations, ranging from squamous hyperplasia to carcinoma in situ and encompassed by the terminology of squamous intraepithelial lesions (SILs). The etiology, classification, genetic changes, and malignant progression of these lesions are reviewed. Tobacco remains the principal etiological factor with gastroesophageal reflux disease recently considered as a possible factor. In contrast, there is little evidence that microbiological agents, especially human papillomavirus infection, are frequently involved in laryngeal carcinogenesis and probably <10% of SILs are driven by biologically active human papillomavirus infection. Light microscopy, despite a degree of subjectivity, remains the mainstay of accurate diagnosis, prognosis, and guidance for a patient's treatment. The currently used classifications, the dysplasia system, squamous intraepithelial neoplasia, and the Ljubljana classification, reflect different standpoints on this important topic. The modified Ljubljana classification, with good interobserver agreement, could be considered as a proposal for a unified classification of laryngeal SILs. This review also briefly discusses recently discovered genetic changes, such as CDKN2A and CTNNB1 genes, and chromosome instability of chromosomes 1 and 7; however, none of these can at present improve histologic diagnosis. Malignant progression of precursor lesions varies from 2% to 74%, according to different studies. Cold-steel microinstruments, CO2 laser, and radiotherapy are used to treat the different grades of precursor lesions. There is as yet no worldwide agreement on the treatment of high-grade lesions and carcinoma in situ.

Laryngeal Papillomatosis Associated Dysplasia in the Adult Population

Objectives:

The objectives were to determine the prevalence of laryngeal dysplasia and associated human papilloma virus (HPV) subtypes in adult patients, 18 years or older, suffering from laryngeal papillomatosis at a tertiary care institution.

Study Design:

Retrospective cohort study.

Methods:

Patients with biopsy proven laryngeal papillomatosis were identified via chart review. All available pathology specimens were reviewed by a dedicated head and neck pathologist to confirm/refute the diagnosis of laryngeal dysplasia, and grade the level of dysplasia. Interrater agreement was compared using cross-tabulation methods. Specimens identified to be positive for dysplasia underwent further testing via in situ hybridization for low-risk (6/11) or high-risk (16/18) HPV subtypes.

Results:

Of the 85 subjects identified to have laryngeal papillomatosis, 24(28%) demonstrated laryngeal dysplasia. There was good interrater agreement on the presence of dysplasia; however, there was only fair agreement on the grade of dysplasia. Of the pathology specimens tested for HPV subtype, the majority of patients (62%) were positive for HPV 6/11, including all high-grade dysplasia patients. Three (12%) dysplasia specimens were negative for both high- and low-risk HPV subtypes.

Conclusions:

We found a 28% prevalence of dysplasia in our patient population with the majority of patients positive for low-risk HPV subtypes indicating that high-risk HPV subtypes do not predispose laryngeal papilloma patients to dysplasia.

Role of Human Papillomavirus in the Pathogenesis of Laryngeal Dysplasia

Objective

A synergistic effect between smoking and alcohol intake is the major cause of premalignant and malignant lesions of the larynx, but the risk factors and pathogenesis of the neoplastic transformation in nonsmokers remain poorly defined. The aim of this retrospective study is to establish the relationship between smoking habits and human papillomavirus (HPV) infection in laryngeal dysplasia.

Study Design

Cross-sectional study.

Setting

Academic university hospital.

Subjects and Methods

HPV DNA was amplified from 30 paraffin-embedded laryngeal dysplasia tissue specimens by the polymerase chain reaction using 2 groups of different consensus primers (MYO9/MY11 and LCRF1-4, E7R1-4). Fifteen samples were taken from smokers and 15 from nonsmokers.

Results

The present investigation failed to demonstrate the HPV genome in all samples of laryngeal precancerous lesions, whereas HPV was detected in 4 laryngeal papilloma samples used as control to confirm the reliability of our method on paraffin-embedded samples.

Conclusions

Although the small number of cases in our series limits the power of our statistical analysis, the absence of viral genomes in the specimens analyzed in this study suggests the lack of a relationship between HPV infection and laryngeal dysplasia in smokers as well as in nonsmokers.

P16(INK4A) immunostaining is a strong indicator for high-risk-HPV-associated oropharyngeal carcinomas and dysplasias, but is unreliable to predict low-risk-HPV-infection in head and neck papillomas and laryngeal dysplasias

Human papillomavirus (HPV) is a risk factor for the development of benign and malignant mucosal head and neck lesions. P16(INK4A) is often used as a surrogate marker for HPV-infection, although there is still controversy with respect its reliability. Our aim was to determine if p16(INK4A) overexpression can accurately predict both high-risk and low-risk-HPV-presence in (pre)malignant and benign head and neck lesions. P16(INK4A) immunohistochemistry was performed on paraffin-embedded tissue sections of 162 oropharyngeal squamous cell carcinomas (OPSCC), 14 tonsillar and 23 laryngeal dysplasias, and 20 tonsillar and 27 laryngeal papillomas. PCR, enzyme-immunoassay and FISH analysis were used to assess HPV-presence and type. Of the 162 OPSCC and 14 tonsillar dysplasias, 51 (31%) and 10 (71%) were HPV16-positive, respectively. All tonsillar papillomas were HPV-negative and four laryngeal dysplasias and 26 laryngeal papillomas were positive for HPV6 or -11. P16(INK4A) immunohistochemistry revealed a strong nuclear and cytoplasmic staining in 50 out of 51 HPV16-positive and 5 out of 111 HPV-negative OPSCC (p < 0.0001) and in all HPV16-positive tonsillar dysplasias, whereas highly variable staining patterns were detected in the papillomas and laryngeal dysplasias, irrespective of the HPV-status. In addition, the latter lesions generally showed a higher nuclear than cytoplasmic p16(INK4A) immunostaining intensity. In conclusion, our data show that strong nuclear and cytoplasmic p16(INK4A) overexpression is a reliable surrogate indicator for HPV16 in OPSCC and (adjacent) dysplasias. For HPV6 or -11-positive and HPV-negative benign and premalignant lesions of the tonsil and larynx, however, p16(INK4A) immunostaining is highly variable and cannot be recommended to predict HPV-presence.

Investigation of a broad-spectrum PCR assay for human papillomaviruses in screening benign lesions of the upper aerodigestive tract

BACKGROUND

A variety of different human papillomavirus (HPV) types can be found in benign and malignant lesions of the upper aerodigestive tract. Therefore a broad-spectrum assay is needed for screening reasons.

METHODS

A PCR system with degenerate consensus primers originating from a very conserved region (e.g. L1) of the HPV genome was applied. The sensitivity level was improved by combining PCR and nested PCR.

RESULTS

A total of 27 biopsies from laryngeal papillomas (9), exophytic (3) and inverted (6) papillomas of the nasal cavity or paranasal sinuses, papillomas of the uvula or soft palate (5), leukoplakias of the larynx (2), seborrheic keratosis (1) and granulation tumor of the tongue (1) were analyzed by the broad-spectrum PCR system. Sixteen cases showed a positive result in either PCR or nested PCR or both.

CONCLUSIONS

It was shown that the applied broad-spectrum PCR system is a reliable tool in the detection of HPV DNA in benign lesions of the upper aerodigestive tract.

The supplementary diagnostic power of selected immunohistochemical, molecular genetic and infective parameters in epithelial hyperplastic laryngeal lesions

OBJECTIVES

MIB-1 and p53 protein expression, loss of heterozygosity (LOH), microsatellite instability (MSI) of di- and mononucleotide repeats, and HPV status were tested for their potential to characterize different stages of epithelial hyperplastic laryngeal lesions (EHLL).

METHODS

Thirty-two EHLL were reclassified according to the Ljubljana classification into simple (SH), abnormal (AbH), atypical hyperplasia (AtH) and carcinoma in situ, and investigated by immunohistochemical methods, PCR and direct sequencing analysis.

RESULTS

MIB-1 increased with progressive grades of EHLL, whereas p53 protein expression was distinctive only between SH and AbH. LOH showed increasing frequency with grades of the lesions, but the distribution of altered loci (9p, 9q, 10q, 11q, 17p) was not qualified to differentiate between the stages. MSI was detected in SH, AbH and AtH without clear correlation to histopathological grading. HPV infection occurred mostly in SH and AbH (both: 66.7%).

CONCLUSION

MIB-1 labeling and allelic loss could assist histopathological diagnosis in the entire spectrum of EHLL, whereas the MSI results point to a genetic instability of the laryngeal mucosa in general and are therefore not helpful in the distinction of different stages of EHLL. However, future molecular genetic analyses should consider more late events of laryngeal carcinogenesis to improve their diagnostic potential. Furthermore, our results indicate that nonrisky and risky EHLL could probably be caused by different exogenous factors.

Human papillomavirus in larynx

OBJECTIVES

The core of the present clinical and basic research knowledge of laryngeal human papillomavirus (HPV) infection is described.

STUDY DESIGN

Review.

METHODS

A computer-aided search of MEDLINE database supplemented by hand searches of key journals was conducted.

RESULTS

One of the tumor-promoting factors in the larynx is the HPV found both in normal laryngeal epithelium and in laryngeal tumors. The most important manifestation of laryngeal HPV infection is laryngeal papillomatosis, a rare disease caused by HPV types 6 and 11. In laryngeal carcinogenesis, the role of HPV remains uncertain. The means of transmission of HPV are partly unknown, and the course of laryngeal HPV infection is unpredictable and variable. Treatment of laryngeal papillomatosis is based on surgery, especially on CO2 laser and shaver. Alpha-interferon is the drug of choice in patients whose response to surgery is poor. However, neither interferon nor other antiviral drugs are able to eradicate the virus from laryngeal mucosa. Little is known about immunological mechanisms involved in laryngeal HPV infection, but in defense against HPV cellular immunity is considered a more important mechanism than humoral immunity. A good experimental model of HPV infection is lacking in which the entire viral life cycle can take place. Organotypic cell cultures (collagen rafts) are useful, but the rate-limiting step in this method is the difficulties in culturing HPV-positive epithelial cells.

CONCLUSIONS

Although laryngeal papillomatosis is clinically well defined, the mechanisms and treatment modalities of laryngeal HPV infection need further investigations.

p53 Codon 72 polymorphism is linked to the development and not the progression of benign and malignant laryngeal tumours

The p53 codon 72 polymorphism, resulting in either an arginine or a proline residue has been proposed to affect the susceptibility of p53 protein to human papilloma virus (HPV) E6-mediated degradation in vitro. However, there are controversial results from several clinical studies in various human tumours. The purpose of our study was to investigate the significance of this p53 genotype with respect to the risk of neoplasia development in Greek patients with benign and malignant laryngeal tumours. Furthermore, we searched for an association between p53 alleles and the presence of HPV in the same series of samples. We found a significant statistical association in the distribution of p53 genotypes between laryngeal lesions and normal samples (P<0.001). Allelic analysis of the patients with both benign and malignant tumours revealed a striking over-representation of the homozygous p53Arg allele compared to normal population (P<0.0003). HPV was detected in only 3 laryngeal samples (1 benign and 2 malignant tumours). This is the first study correlating the p53 codon 72 polymorphism in laryngeal tumours. Our results provide evidence that this p53 polymorphism may be implicated at the early stages of the disease and concerns predisposition to premalignant laryngeal lesions rather than to progression from benign tumour toward malignancy. Moreover, we demonstrate that the p53Arg homozygous genotype affects the predisposition for laryngeal tumours while the heterozygous status does not. The low incidence of HPV infection suggests that it is not a major oncogenic factor in the development of laryngeal tumours but may have synergistic action with specific genotypes of p53 gene.

Human papillomavirus in conjunctival papilloma

AIM

To examine conjunctival papillomas for the presence of human papillomavirus (HPV) and koilocytosis.

METHODS

Archival paraffin embedded tissue from 55 conjunctival papillomas was analysed for the presence of HPV by polymerase chain reaction and subsequent filter hybridisation. Histological sections of the 55 papillomas were evaluated for the presence of koilocytosis.

RESULTS

HPV was present in 48 of 52 (92%) beta globin positive papillomas. HPV type 6/11 were found in 40 of 47 investigated papillomas and a double infection with HPV 6/11 and 16 was identified in a single papilloma. In six papillomas the HPV type could not be identified. Koilocytosis was present in 22 of 55 papillomas (40%).

CONCLUSION

There is a strong association between HPV and conjunctival papillomas. HPV type 6/11 is the most common HPV type in conjunctival papilloma. The sensitivity of koilocytosis as an indicator of HPV in conjunctival papilloma is low.

Detection of human papillomavirus in laryngeal squamous dysplasia and carcinoma. An in situ hybridization and signal amplification study

We examined the presence of human papillomavirus (HPV) DNA in 65 cases of laryngeal squamous dysplasia and carcinomas using in situ hybridization with signal amplification in paraffin sections. Hybridization was performed with biotinylated DNA probes for HPV 6/11, 16/18, 31/33 and wide-spectrum HPV (6, 11, 16, 30, 31, 45, 51 and 52). HPV DNA was found in 7 cases of the total sample (10.7%); it was also found in 4 out of 45 (8.8%) cases of invasive carcinoma and in 5 out of 33 (15.5%) cases of squamous dysplasia. Morphological signs suggestive of HPV infection were observed in 35.5% of our sample but they were not related to HPV DNA positivity. In conclusion, HPV probably plays little, if any, role in laryngeal carcinogenesis among the population studied.

Clinical applicability of the Ljubljana classification of epithelial hyperplastic laryngeal lesions

The diagnosis, prognosis, and choice of treatment of various laryngeal lesions depends almost entirely on the interpretation of changes in the covering epithelium. These abnormalities, referred to as epithelial hyperplastic laryngeal lesions, have been graded according to the Ljubljana classification into simple, abnormal and atypical (risky epithelium) hyperplasia and carcinoma in situ. The aim of this study was to evaluate the clinical applicability and prognostic value of this classification and to determine the incidence of malignant transformation. A retrospective clinical-pathological analysis was performed in a series of 4167 patients with 4574 biopsies, treated from 1979 to 1994. Simple (benign prickle cell) hyperplasia was the predominant grade in nodules, polyps, Reinke's oedema, granulomas, and papillomas, accounting for 37.6-68.6% of cases. In chronic laryngitis, abnormal (benign basal cell) hyperplasia was predominant with 43.9% of cases. Atypical ('risky') hyperplasia was observed almost exclusively in patients with chronic laryngitis (16.1%) and papillomas (10.1%), and only exceptionally in patients with vocal cord nodules (0.9%) and Reinke's oedema (0.3%). The percentage of malignant transformation in atypical hyperplasia was 11.6% (13/112 patients in 2-12 years), while in simple and abnormal hyperplasia, it was 0.3% (8/2920 patients in 1.5-11 years). The data support the concept of the Ljubljana classification dividing epithelial hyperplastic laryngeal lesions into benign (simple and abnormal hyperplasia), potentially malignant (atypical hyperplasia) lesions and carcinoma in situ.

Laryngeal cancer and human papillomavirus: HPV is absent in the majority of laryngeal carcinomas

Thirty laryngeal carcinomas from patients without pre-existing laryngeal papillomatosis were examined by PCR for the presence of HPV DNA. The utmost care was taken during sectioning of the tissue blocks and DNA-extraction in order to avoid false positive results. Three pairs of consensus primers were used: MY9/MY11, GP5+/GP6+ and CPI/CPII. HPV was detected in 1/30 carcinomas. The HPV type present could not be determined, but it was not type 6, 11, 13, 16, 18, 30, 31, 33, 35 or 45. In other studies the reported frequency of HPV in laryngeal carcinomas, as estimated by PCR, varies between 3-85%. The reasons for this unacceptable variation in reported results are discussed. The present results indicate that HPV DNA does not have a major role in malignant tumours of the larynx in patients without pre-existing recurrent laryngeal papillomatosis.

Criteria for grading in the Ljubljana classification of epithelial hyperplastic laryngeal lesions. A study by members of the Working Group on Epithelial Hyperplastic Laryngeal Lesions of the European Society of Pathology

AIMS

To validate histological criteria for the grading of epithelial hyperplastic laryngeal lesions (EHHL) (dysplastic laryngeal lesions), we used a system that had been devised and tested in Ljubljana, Slovenia over many years and was felt to be more appropriate to laryngeal pathology than is the commonly-used model of intraepithelial neoplasia in the cervix.

METHODS AND RESULTS

Vocal cord biopsies of 45 patients with a broad spectrum of EHLL were reviewed. Detailed histological criteria were formulated for each of the four grades of EHLL in the Ljubljana classification, comprising simple hyperplasia (benign spinous layer augmentation), abnormal hyperplasia (benign basal and parabasal layer augmentation), atypical hyperplasia (risky for malignancy) and carcinoma in situ (actually malignant, but without invasion).

CONCLUSIONS

Using these criteria a high degree of concordance of histological diagnoses of grading levels for the Ljubljana classification was achieved between the pathologists of the Working Group. The system was found to be more precise for routine diagnostic work than the others in vogue. The different grades of the Ljubljana classification correspond to significantly different levels yielded in each grade by the semiobjective methods of quantitative morphometry and immunohistochemistry.

An aggressive and invasive growth of juvenile papillomas involving the total respiratory tract

A malignant course of juvenile laryngeal papillomatosis has rarely been reported. In the present case the patient had had laryngeal papillomas since the age of three years. The papillomas gradually spread to the entire respiratory system, and during 30 years the patient was operated on more than 80 times. At present an invasive tumour spreading from the tongue into the parapharyngeal space, extending to the cranial base, has been demonstrated by magnetic resonance imaging (MRI). Intralesional therapy with Cidofovir, a promising antiviral drug against human papillomavirus (HPV) infection, was started with some clinical effect, although only on the superficial tumour growth. Histology of removed tumour tissue has demonstrated a mixture of exophytic and inverted growth pattern, and has mainly been interpreted as benign, in spite of a focally high mitotic index and an intermittent lack of maturation in the epithelium. In the most recent biopsies a verrucous carcinoma has been diagnosed. Expression of p53 was noted to increase in papillomas with time. All samples have been shown to harbour HPV 11, but no other HPV types.