Human papillomavirus: clinical significance and malignant potential

Atypical mid rectal localization of squamous cell carcinoma: A case report and literature review

INTRODUCTION AND IMPORTANCE

Squamous cell carcinoma occurring in the rectum is a very rare malignancy. When encountered in the gastrointestinal tract, it usually involves the esophagus or the anal canal. The rare incidence of rectal squamous cell carcinomas has raised quite a few questions on the hypothetical etiologies and prognosis.

CASE PRESENTATION

In this report, we present a case of a 73 years old woman who presented a rare case of squamous cell carcinoma, at 8 cm from the anal margin.

CLINICAL DISCUSSION

Optimal treatment sequence of such an uncommon disease is yet to be standardized, surgery was the gold standard management for rectal squamous cell carcinoma, but exclusive chemoradiotherapy is slowly but surely supplanting it.

CONCLUSION

This case allows us to engage in discussions over the uncommon location of the rectal SCC and its current treatment management. The exclusive chemoradiation therapy has given excellent results becoming the gold standard treatment of this rare entity.

Prospective, Multi-Center Study of the Anatomic Distribution of Recurrent Respiratory Papillomatosis

OBJECTIVES/HYPOTHESIS

To create a model of the anatomic distribution, recurrence, and growth patterns of recurrent respiratory papillomatosis (RRP).

STUDY DESIGN

Prospective, multi-institutional cohort study.

METHODS

Adult patients with a diagnosis of RRP evaluated between August 1, 2018 and February 1, 2021 at six participating centers were invited to enroll. At each office or operating room encounter, laryngologists recorded the location and size of RRP lesions using a 22-region schematic. A generalized linear mixed effects model was used to compare region variations in lesion prevalence and recurrence.

RESULTS

The cohort comprised 121 patients: 74% were male, 81% had been diagnosed with adult-onset RRP, and a plurality (34%) had undergone 0 to 3 RRP interventions prior to enrollment. Across the study period, the odds of a lesion occurring in the glottis was significantly higher (odds ratio [OR]: 26.51; 95% confidence interval [CI]: 11.76-59.75, P < .001) compared with all other areas of the larynx and trachea. Within the true vocal folds, the membranous vocal folds had significantly higher odds (OR: 6.16; 95% CI: 2.66-14.30, P < .001) of lesion occurrence compared to the cartilaginous vocal folds. Despite these strong trends in lesion distribution, there were no differences in the odds of lesion recurrence, growth, or in the time to recurrence, between anatomic subsites.

CONCLUSIONS

RRP lesions are most likely to occur in the glottis, particularly the membranous vocal folds, compared with other regions of the larynx or trachea. However, all lesions demonstrate similar behavior with respect to recurrence, growth, and time to recurrence regardless of anatomic location.

LEVEL OF EVIDENCE

3 Laryngoscope, 132:2403-2411, 2022.

Trace Elements Levels in Serum of Patients with Recurrent Respiratory Papillomatosis

Recurrent respiratory papillomatosis (RRP) is a chronic airway disease characterized by unpredictable recurrences and relapses. Our study aimed to identify the role of trace elements, a proven risk factor for various malignancies, in the development of papilloma and to correlate their serum levels with various disease parameters. 32 RRP patients with 20 age-matched controls were recruited in the study. Analysis of serum trace elements was performed by atomic absorption spectrophotometry in whole blood samples from cases and controls. The serum levels of trace elements were correlated with age of onset, history of previous surgeries, tracheostomy status, Derkay's score, and presence of dysplasia. Among the 32 cases there were 18 males and 14 females with a mean age of 20.85 years (range: 3-60 years). The mean serum levels of Thallium, Zinc, and Gallium were higher among cases compared to their controls whereas the levels of Arsenic, Copper, Cobalt, Selenium, Cadmium, and Lead were higher in control subjects compared to RRP patients. There was a statistically significant correlation of serum level of Cobalt with more than 3 surgeries per year (p = 0.02), Gallium and Thallium with Derkay's score of more than 20 (p = 0.04 and 0.05) and Lead, Arsenic and Gallium with presence tissue dysplasia (p = 0.05, 0.04 and 0.04). Our study had shown a variable association of trace elements in RRP patients. The usefulness of these values need to be completely elucidated and our study calls for future investigations to identify the casual association of various trace elements in the pathogenesis of RRP.

Molecular mechanism of microRNA-26a regulation of phosphatase and tensin homolog gene in condyloma acuminatum and penile squamous cell carcinoma

OBJECTIVE

To investigate the expression levels and mechanisms of microRNA (miRNA) 26a (miR-26a) and phosphatase and tensin homolog (PTEN) in patients with human papillomavirus (HPV)-induced condyloma acuminatum (CA) and penile squamous cell carcinoma (PSCC).

METHODS

Thirty-one patients with HPV-positive CA and 28 with HPV-positive PSCC were included in this retrospective, cross-sectional study. PTEN mRNA and miR-26a levels in lesion tissues, blood, and urine were analyzed by quantitative reverse transcription polymerase chain reaction, and PTEN protein was detected by western blot and enzyme-linked immunosorbent assay. Cell proliferation was assessed by MTT assay. The interaction between miR-26a and PTEN was predicted by bioinformatics analysis and confirmed by dual luciferase reporter assay.

RESULTS

PTEN mRNA and protein levels were significantly lower and miR-26a levels were significantly higher in all samples from patients with PSCC compared with the CA group. Bioinformatics analysis and luciferase reporter assay confirmed PTEN as a target gene of miR-26a. Up-regulation of miR-26a significantly increased the proliferation of Penl1 PSCC cells.

CONCLUSIONS

PTEN expression is down-regulated and miR-26a levels are up-regulated in PSCC compared with CA. PTEN is a direct target gene of miR-26a. These results suggest that miR-26a might regulate HPV-positive progression from CA to PSCC through modulating PTEN.

Pembrolizumab Induced Acute Persistent Airway Disease in a Patient with Recurrent Respiratory Papillomatosis (RRP)

OBJECTIVE

To present an uncommon but serious, recently identified complication of checkpoint inhibitor therapy in a patient treated with pembrolizumab infusion for disseminated recurrent respiratory papillomatosis (RRP).

METHODS

Case report.

RESULTS

A 43-year-old woman with underlying asthma developed acute hypoxic respiratory failure within 24 hours of her third infusion of pembrolizumab for treatment of intractable, disseminated recurrent respiratory papillomatosis. Pulmonary function testing revealed a severe intra-thoracic obstructive ventilatory defect. Discontinuation of pembrolizumab, ventilatory support, and treatment with systemic and inhaled corticosteroids resulted in resolution of respiratory failure; however, her underlying asthma remains poorly controlled.

CONCLUSION

To our knowledge, this case is the first report of pembrolizumab-induced obstructive respiratory failure in a patient being treated for RRP.

Spontaneous Regression of Recurrent Respiratory Papillomatosis with HPV Vaccination: A Case Study

OBJECTIVES

Recurrent respiratory papillomatosis (RRP) is characterized by recurrent laryngeal papillomas and treated with repeated surgical excision. The human papillomavirus (HPV) vaccine prevents infection with strains of HPV unrelated to RRP, and has recently been shown to increase the interval between surgeries when used as an adjuvant. The objective of this study was to report one case from our institution in which HPV vaccination was found to induce spontaneous regression of disease, absent of surgical intervention or use of other adjuvants.

STUDY DESIGN

Retrospective case study.

METHODS

Records of one patient with RRP receiving partial HPV vaccination was reviewed with attention to videolaryngostroboscopic findings, Derkay score, need for surgical intervention, and voice quality.

RESULTS

Spontaneous regression of disease after vaccination was seen in this patient, as evidenced by reduced tumor burden and decreased voice handicap index. The patient was a 30-year old female, who had improved disease burden and voice quality after one dose and total resolution of disease following the second dose. Vaccine administration was the sole therapeutic mechanism.

CONCLUSIONS

These findings suggest that HPV vaccination can treat RRP without surgical intervention. Further studies are needed to investigate the underlying mechanism of disease regression and which patients may benefit most. We believe that HPV vaccination for all patients with RRP, even over the age of 45 years, may decrease treatment costs for individuals and the healthcare system overall.

RECCURENT GIANT CONDYLOMATA ACUMINATA CAUSED BY HUMAN PAPILLOMA VIRUS IN HIV WITH HOMOSEXUAL MALE

Perianal giant condylomata acuminate (GCA) is a rare clinical condition associated with low-risk Human papillomavirus (HPV) type 6 and 11 infections. Human Immunodeficiency Virus (HIV) infection is one of the risk factors for GCA, that can increase the condylomata acuminate incidence and spread caused by HPV. A 28-year-old man came with a cauliflower-like mass complaint in his perianal and anal since 2 months ago. The patient did not complain of pain or itching on the mass but often bled when defecating. The patient is a male who has sex with men (MSM) and often changes partners. He has been diagnosed with HIV since 11 months ago and regularly taking anti-retroviral drugs, Efavirenz 600 mg daily. He was also diagnosed having lung tuberculosis at the same time, got 6 months treatment and was declared cured. The venereological examination of the perianal and anal region revealed erythematous and grayish stem-shaped vegetation and papules, verrucous surface, multiple, well defined, with 3 x 1.5 x 2 cm in size. A positive act of white examination was obtained. Blood tests revealed CD+4 230 cells /μL. Polymerase chain reaction (PCR) examination for HPV obtained HPV types 6 and 11 infections. Histopathologic examination revealed acanthosis, papillomatosis, and hyperkeratotic epidermis and koilocytotic cells. The patient was treated with electrodesiccation three times but obtained mass in anal getting bigger with a size of 6 x 3 x 3 cm. Therefore, he agreed to be referred to the surgical department with an extensive surgical excision plan. Screening of GCA using PCR is not a routine examination but PCR has high sensitivity and specificity for determining the type of HPV, is useful for determining GCA prognosis and therapy, and is recommended for malignant and possible GCA recurrence detection

Diagnostically challenging human papillomavirus-associated primary squamous cell carcinoma of the rectum with metastasis in both ovaries: a case report

Introduction

Squamous cell carcinomas of the rectum are extremely rare and their pathogenesis is still under debate. Their proper diagnosis and treatment may thus be challenging.

Case presentation

A 52-year-old Caucasian woman was transferred to our department with a history of pelvic pain. Colonoscopy revealed a small tumorous lesion of the upper rectum and an endoscopic biopsy showed infiltration of the rectal mucosa by a squamous cell carcinoma. Afterward, tumorous lesions were found on imaging in both her ovaries. A laparoscopy with adnexectomy and anal mapping was performed and revealed tumor masses of squamous cell carcinoma in both ovaries. Based on the large size of the ovarian tumors and the concurrence of extensive, partly ciliated, macrocystic epithelium in one of the ovaries, a diagnosis of ovarian squamous cell carcinoma arising from a mature teratoma was rendered. However, human papillomavirus genotyping analyses were positive for human papillomavirus-16 in both the rectal tumor and ovarian tumors leading to a final diagnosis of a human papillomavirus-associated rectal squamous cell carcinoma metastatic to both ovaries. Neoadjuvant chemoradiation therapy of her rectum, total mesorectal excision, and hysterectomy were performed followed by adjuvant chemotherapy.

Conclusion

Colorectal squamous cell carcinoma is a rare disease. In cases of colorectal squamous cell carcinoma, metastatic disease at any other location has to be excluded. Human papillomavirus genotyping is essential in this context. Discussion of the treatment strategies should be interdisciplinary and include chemoradiation therapy and radical surgery.

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.

Laryngeal distribution of adult-onset recurrent respiratory papillomatosis: A longitudinal study

OBJECTIVES/HYPOTHESIS

To describe recurrence patterns in patients with recurrent respiratory papillomatosis (RRP) following surgical intervention.

STUDY DESIGN

Single-center, retrospective, longitudinal case series.

METHODS

Initial and follow-up laryngoscopic examinations of seven previously untreated adult-onset RRP patients were reviewed. Patients were followed longitudinally for periods ranging from 3 months to 7 years. Lesion locations were recorded using a twenty-one region laryngeal schematic, and maps were generated to illustrate the distribution of disease before and after cold-knife or potassium-titanyl-phosphate laser intervention. Univariate and multivariate analyses were employed to examine variables affecting recurrence patterns.

RESULTS

Across all patients, a statistically significant correlation between initial distribution and primary recurrence was observed. Seventy-five percent of new lesions were adjacent to regions with preexisting disease; 83% of new glottic lesions were adjacent to preexisting glottic lesions, and 66% of supraglottic lesions were adjacent to preexisting supraglottic regions. No statistically significant differences in recurrence rate were observed across sites.

CONCLUSIONS

In previously untreated patients with adult-onset recurrent respiratory papillomatosis, lesions tended to recur either in the same regions or regions adjacent to those affected at the time of initial surgery.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:1993-1997, 2019.

Synchronous Squamous Cell Carcinoma of the Anorectum and Proctosigmoid-a Case Report

Primary squamous cell carcinoma of the rectum is extremely rare. Squamous cell carcinoma of the anorectum is a known entity evaluation and treatment protocols have been well defined. The occurrence of squamous cell carcinoma of rectosigmoid in concurrence with squamous cell carcinoma of the anal canal is extremely rare and the first case to be reported in the literature. A 48-year-old male patient presented with difficulty in passing stools. The clinical examination, colonoscopy, and the histopathology revealed synchronous proctosigmoid and the anorectal neoplasm. A case like this will pose a diagnostic challenges; squamous cell carcinoma of the rectum is not defined in the medical literature; synchronous squamous cell carcinoma will pose both diagnostic dilemmas and treatment challenges like whether to conserve the sphincter or not. Because squamous cell carcinoma of the anorectum can be treated by chemoradiotherapy, even this case is initially thought of treating by neoadjuvant chemoradiotherapy followed by low anterior resection followed by adjuvant treatment. Since there was no medical literature to support this treatment, ultimately multidisciplinary tumor board decision was made for abdominoperineal resection. Patient was treated with abdominoperineal resection and adjuvant chemoradiation. The diagnostic dilemmas and the management issues have been discussed.

Current and future management of recurrent respiratory papillomatosis

Objectives

Recurrent respiratory papillomatosis (RRP) is a chronic disease of the respiratory tract that occurs in both children and adults. It is caused by the human papillomavirus (HPV), in particular low‐risk HPV6 and HPV11, and aggressiveness varies among patients. RRP remains a chronic disease that is difficult to manage. This review provides perspectives on current and future management of RRP.

Results

The current standard of care is surgical excision, with adjuvant therapies as needed. Surgical management of RRP has evolved with the introduction of microdebriders and photoangiolytic lasers; the latter can now be used in the office setting. Numerous adjuvant pharmacologic therapies have been utilized with some success. Also, exciting preliminary data show that HPV vaccines may prolong the time to recurrence in the RRP population. There is also optimism that wide‐spread HPV vaccination could reduce RRP incidence indirectly by preventing vertical HPV transmission to newborns.

Conclusion

To date, the biology of RRP is not well understood, although it has been noted to become more aggressive in the setting of immune suppression. Additional research is needed to better understand immune system dysfunction in RRP such that immunomodulatory approaches may be developed for RRP management.

Level of Evidence

4

Complete pathologic response after chemoradiotherapy in a patient with rectal squamous cell carcinoma: a case report

Squamous cell carcinoma (SCC) of the rectum is a rare disease. A 59-year-old man presented with SCC of the middle rectum located 10 cm from the anus. The stage of the tumor was revealed to be T3N+M0. The patient received a combined treatment with cisplatin and fluorouracil in concomitance with external radiation therapy. He then underwent an anterior resection of the rectum. The postoperative histopathological findings classified the tumor as ypT0N0 with cancer-free margins and lymph nodes. Treatment of SCC remains very challenging, and the acquisition of more consistent data is needed.

Circumferential anal giant condyloma acuminatum: a new surgical approach

INTRODUCTION

Perianal giant condyloma acuminatum is a rare clinical condition related to human papillomavirus infection and characterized by a circumferential, exophytic, cauliflower-like mass with an irregular warty surface localized in the anal region.

TECHNIQUE

A circular incision with a diathermocoagulator was performed on macroscopically healthy skin, 1 cm from the margin of the lesion. The dermis was divided from the subcutaneous tissue. This way, a mucocutaneous cylinder including the whole lesion was obtained. A median radial incision was carried out to open the cylinder at its front. A progressive circumferential section on healthy mucosa (≈1 cm above the margin of the lesion) by means of a radiofrequency dissector allowed for the complete removal of the mass. The healthy mucosa of the anal canal was pulled out by Allis forceps and was sutured to the external margin of the internal sphincter with single layer of Vicryl (polyglactin 910) 2-0 sutures.

RESULTS

Two months after surgery, no findings of anal stenosis or mucosal ectropion were reported. At the 1-year follow-up there was no recurrence of condylomatosis in any of the 3 cases.

CONCLUSIONS

Our procedure seems simpler to perform when compared with other techniques and reduces hospital stay and complications such as anal stenosis and mucosal ectropion.

Nucleotide and phylogenetic analysis of human papillomavirus types 6 and 11 isolated from recurrent respiratory papillomatosis in Brazil

There are few studies about the distribution of natural molecular variants of low-risk HPVs. Our aim was to evaluate the E6 early gene variability among HPV-6 and HPV-11 isolates detected in recurrent respiratory papillomatosis (RRP) samples obtained in a cohort of Brazilian patients. We also performed a phylogenetic analysis in order to compare nucleotide sequences identified in our study with previously reported isolates from different anatomic sites (laryngeal papillomas, genital warts, cervical cancer and anal swabs) obtained from other parts of the world to determine the phylogenetic relationships of variants detected in Brazil. The complete coding region of the E6 gene of 25 samples was cloned and sequenced: 18 isolates of HPV-6 (72%) and 7 isolates of HPV-11 (28%). A total of four different HPV-6 genomic variants and two HPV-11 genomic variants was identified. It was not possible to correlate specific variants with disease severity. Phylogenetic trees for both HPV types were constructed enclosing both E6 sequences detected in our study and formerly published sequences. In both phylogenetic trees, the sequences from Brazil did not group together. We could not establish a geographical association between HPV-6 or HPV-11 variants, unlike HPV-16 and HPV-18.

Squamous cell cancer of the rectum

Squamous cell carcinoma of the rectum is a rare malignancy. It appears to be associated with chronic inflammatory conditions and infections. The clear association seen between Human Papilloma Virus and various squamous cancers has not been firmly established for the squamous cell cancer of the rectum. The presentation is nonspecific and patients tend to present with advanced stage disease. Diagnosis relies on endoscopic examination with biopsy of the lesion. Distinction from squamous cell cancer of the anus can be difficult, but can be facilitated by immunohistochemical staining for cytokeratins. Staging of the cancer with endoscopic ultrasound and computed tomography provides essential information on prognosis and can guide therapy. At present, surgery remains the main therapeutic option; however recent advances have made chemoradiation a valuable therapeutic addition. Squamous cell carcinoma of the rectum is a distinct entity and it is of crucial importance for the practicing Gastroenterologist to be thoroughly familiar with this disease. Compared to adenocarcinoma of the rectum and squamous cell cancer of the anal canal, squamous cell carcinoma of the rectum has different epidemiology, etiology, pathogenesis, and prognosis but, most importantly, requires a different therapeutic approach. This review will examine and summarize the available information regarding this disease from the perspective of the practicing gastroenterologist.

Correlation between laminin-5 immunohistochemistry and human papillomavirus status in squamous cervical carcinoma

BACKGROUND

Human papillomavirus (HPV) plays a critical role in the carcinogenesis of squamous cervical carcinoma. Integration of viral DNA into the host genome is a major contributing factor to malignant transformation. Viral load may influence integration.

AIMS

To compare HPV status (type, viral load, integration status) between normal samples, carcinoma in situ and invasive carcinoma in order to elucidate the role of HPV in progression to invasive lesions.

METHODS

The study population comprised 10 biopsy samples from each diagnostic group. Laminin-5 immunohistochemistry was performed to distinguish invasive carcinoma from non-invasive high-grade lesions. Real-time PCR was used to detect specific HPV types, viral load and integrated HPV, with quantification of viral E2 and E6 genes.

RESULTS

Invasive carcinomas contained a higher number of laminin-5 immunoreactive cells as compared to non-invasive lesions. Almost all samples contained HPV, with a higher viral load and copy number of HPV16 integrated in E2 in cases of laminin-5 immunoreactivity and cases of invasive carcinoma. High HPV16 viral load was associated with more integrated copies in E2.

CONCLUSIONS

HPV is important in progression from carcinoma in situ to invasive carcinoma. Viral load and HPV integration influence the development of cervical cancer towards invasiveness. Overall HPV status may be more predictive of patient outcome and may influence patient management.

Malignant progression of anal intra-epithelial neoplasia

BACKGROUND

Anal intra-epithelial neoplasia (AIN) is believed to be a precursor to squamous cell carcinoma of the anus. The risk of developing anal cancer in patients with AIN, although known to occur, has been thought to be relatively low. This study reviews our experience with AIN, reviewing the incidence and risk factors for development of invasive malignancy and the outcome of present management strategies.

METHODS

This study examined a cohort of 72 patients identified from a prospective database with AIN from a single institution between January 1996 and December 2004. A single pathologist examined all pathological specimens.

RESULTS

There were 72 patients (52 women) and the median age was 49 years (range, 18-81 years). We identified progression of AIN to invasive malignancy in eight patients despite undergoing surveillance. Regression following treatment or biopsy was seen in 25 patients. Four patients required stomas for incontinence following treatment.

CONCLUSION

This study has shown a high rate of progression to invasive malignancy (11%) with AIN despite surveillance. The patients at risk of developing squamous cell carcinoma were the immunocompromised and those with genital intra-epithelial field change. Treatment of AIN has significant complications and despite treatment, invasive cancers do occur. Decisions made for treatment of AIN can affect treatment choices if invasive malignancy develops.

Intravenous cidofovir treatment for recalcitrant warts in the setting of a patient with myelodysplastic syndrome

Cidofovir is an acyclic nucleoside phosphonate with broad-spectrum activity against DNA viruses, including human papilloma virus (HPV). However, data on the efficacy of cidofovir in an immunosuppressive setting remain contradictory. We report for the first time on the promotion of the healing of recalcitrant warts in a patient with myelodysplastic syndrome with intravenous cidofovir treatment.

AIDS and HIV infections: uncommon presentations

Infection with HIV or AIDS has a great impact on skin diseases, not only by affecting the immune system and thereby host defense against bacterial, viral, or mycotic infection, but also by changing tumor immune response and autoimmune reactivity. In the present review, emphasis will be made on infectious diseases, including sexually transmitted disease, inflammatory skin disease, and neoplasias. Knowledge of changing disease pattern with HIV/AIDS may help the clinical dermatologist and venerologist to identify dermatoses and act in the most appropriate manner to support the patient.

Vaccination against multiple HPV types

Vaccines against the most common human papillomavirus (HPV) types are currently under development. Epidemiologic data suggest that the transmission dynamics of different HPV types are not independent. Some studies indicate that interactions among HPV types are synergistic, where infection with one type facilitates concurrent or subsequent infection with another HPV type. Other studies point to antagonistic interference among HPV types. Here we develop a mathematical model to explore how these interactions may either enhance or diminish the effectiveness of vaccination programs designed to reduce the prevalence of the HPV types associated with cervical cancer. We analyze the local stability of the infection-free and boundary equilibria and characterize the conditions leading to a coexistence equilibrium. We also illustrate the results with numerical simulations using realistic model parameters. We show that if interactions among HPV types are synergistic, mass vaccination may reduce the prevalence of types that are not even included in the vaccine.

Buschke-Löwenstein tumor in childhood: a case report

Buschke-Löwenstein tumor or giant condyloma is a warty verrucous lesion, characterized by slow growth, locally infiltrating and disfiguring lesions. Despite its benign histological appearance and low risk of metastasis, Buschke-Löwenstein tumor is an intermediate lesion between condyloma acuminatum and verrucous carcinoma. It has been linked to human papilloma virus, mainly subtypes 6 and 11. Other factors implicated in this disease include poor hygiene, chronic irritation, promiscuity, and cellular immunocompromised states. It rarely occurs in children. The first line of treatment is radical surgical excision with or without adjuvant chemotherapy. We report the case of a 12-year-old girl with a giant perianal condyloma that was treated with surgical excision and a 6-week course of 5-fluorouracil beginning 6 weeks after surgery, with excellent functional and cosmetic results.

Analysis of human papillomavirus prevalence and TP53 polymorphism in head and neck squamous cell carcinomas

Head and neck squamous cell carcinoma is a disease associated with tobacco and alcohol abuse. There is evidence that the oncogenic human papillomavirus (HPV) may also be a risk for upper aerodigestive tract cancers. High-risk HPVs encode two early proteins, E6 and E7, that can bind to p53 and pRb, respectively, and induce its degradation or inactivation. The TP53 gene has a single polymorphism at codon 72 of exon 4 that encodes either arginine (Arg) or proline (Pro). The purpose of this study was to evaluate the role of HPV infection and TP53 polymorphism in head and neck cancer. We analyzed 50 tumors, as well swabs of oral mucosa from 142 control individuals, with a polymerase chain reaction technique. The prevalence of HPV in controls was 10.6% and in cancer specimens 16%. The frequency distribution of genotypes in controls was 50% Arg/Arg, 43% Arg/Pro and 7% Pro/Pro; in tumors, it was 52% Arg/Arg, 32% Arg/Pro, and 16% Pro/Pro. Contrary to the results of some studies on cervical cancer, no association between any TP53 genotype or allele and the development of head and neck cancer was observed, regardless of HPV status, except for the Pro/Pro genotype, which is associated with the absence of HPV. The arginine allele appears to protect against head and neck cancers. Also, the data showed that HPV infection results in no increased risk of developing head and neck tumors.

Does human papilloma virus have a role in squamous cell carcinoma of the colon and upper rectum?

AIM

To determine if Human Papilloma Virus (HPV) has a role in the aetiology of adenosquamous and squamous cell carcinoma of the colon and upper rectum, and to describe the clinical features seen in our patients with this condition.

METHODS

Patients were identified with squamous cell carcinoma (SCC), adenosquamous carcinoma (Ad-SCC), or adenocarcinoma with squamous metaplasia (AA) of the colon and upper rectum over the 10 years from 1/1/1990 to 31/12/1999. Patients were identified from a prospective pathology database. All tumours were at least 5cm above the dentate line. Pathology blocks were stained using the Peroxidase labelled Streptavidin technique using mouse monoclonal antibody NCL-HPV-4C4, which identifies HPV 6, 11, 16 and 18. Age, gender and site matched controls (colorectal adenocarcinomas) were also stained. The clinical presentation and management was reviewed from the case notes.

RESULTS

Twenty patients were identified from a pathological database of 2351 colorectal cancers (0.85% of colorectal cancers). 0/20 of the study patients (SCC, Ad-SCC, AA) or adenocarcinoma controls stained positively for HPV 6, 11, 16, 18. The clinical presentation was similar to patients presenting with adenocarcinomas.

CONCLUSIONS

The peroxidase labelled streptavidin technique is an immunohistochemical technique with high specificity but lower sensitivity. There was no apparent association between HPV 6, 11, 16, 18 and squamous cell and adenosquamous carcinoma of the colon and rectum using this technique. Clinical features are similar in squamous and adenosquamous colorectal carcinomas to colorectal adenocarcinomas.