Integration of HPV6 and Downregulation of AKR1C3 Expression Mark Malignant Transformation in a Patient with Juvenile-Onset Laryngeal Papillomatosis

Abstract

Juvenile-onset recurrent respiratory papillomatosis (RRP) is associated with low risk human papillomavirus (HPV) types 6 and 11. Malignant transformation has been reported solely for HPV11-associated RRP in 2–4% of all RRP-cases, but not for HPV6. The molecular mechanisms in the carcinogenesis of low risk HPV-associated cancers are to date unknown. We report of a female patient, who presented with a laryngeal carcinoma at the age of 24 years. She had a history of juvenile-onset RRP with an onset at the age of three and subsequently several hundred surgical interventions due to multiple recurrences of RRP. Polymerase chain reaction (PCR) or bead-based hybridization followed by direct sequencing identified HPV6 in tissue sections of previous papilloma and the carcinoma. P16INK4A, p53 and pRb immunostainings were negative in all lesions. HPV6 specific fluorescence in situ hybridization (FISH) revealed nuclear staining suggesting episomal virus in the papilloma and a single integration site in the carcinoma. Integration-specific amplification of papillomavirus oncogene transcripts PCR (APOT-PCR) showed integration in the aldo-keto reductase 1C3 gene (AKR1C3) on chromosome 10p15.1. ArrayCGH detected loss of the other gene copy as part of a deletion at 10p14-p15.2. Western blot analysis and immunohistochemistry of the protein AKR1C3 showed a marked reduction of its expression in the carcinoma. In conclusion, we identified a novel molecular mechanism underlying a first case of HPV6-associated laryngeal carcinoma in juvenile-onset RRP, i.e. that HPV6 integration in the AKR1C3 gene resulted in loss of its expression. Alterations of AKR1C gene expression have previously been implicated in the tumorigenesis of other (HPV-related) malignancies.

Human Papillomavirus-Related Head and Neck Cancer

“…This supports the idea of clonal selection by HPV integration towards more aggressive tumors. Interestingly, HPV DNA integration in the AKR1C3 gene (a hydroxysteroid dehydrogenase involved in the regulation of androgens and estrogens) has been attributed to malignant transformation in a patient with HPV type 6-related juvenile-onset recurrent respiratory papillomatosis [33]. However, in tonsillar cancer, HPV DNA integration was found to be associated with a favorable prognosis [31].…”

Global Genomic Diversity of Human Papillomavirus 6 Based on 724 Isolates and 190 Complete Genome Sequences

“…It is the major etiological agent of anogenital warts and laryngeal papillomas, the most frequent benign tumors of the anogenital region and upper respiratory tract (2)(3)(4)(5). In addition, HPV6 has been associated with Buschke-Löwenstein tumor (6) and with sporadic cases of anal (7), vulvar (8), penile (9), and head and neck (10) cancers, and it is the most prevalent low-risk type in HPV-positive women with normal cytology, with a global prevalence of 0.8% (11). Due to its clinical importance, HPV6 has been included in both the quadrivalent and nonavalent prophylactic HPV vaccines (12).…”

Small cell neuroendocrine carcinoma of tracheostomy site in a patient with a history of juvenile laryngeal papillomatosis

“…HPV6 is the most common HPV subtype found in JP: having a prevalence of 50–84% and HPV11 of 25–37% 8. Both HPV6 and HPV11 have been associated with malignant transformation to SCC, although HPV11 is considered to be at higher risk 2. Currently, it is unclear how HPV infection can lead to malignancy.…”

“…It can occur at any point in the airway but most commonly affects the larynx 2. The condition is associated with human papillomavirus (HPV) with subtypes 6 and 11 the most commonly implicated 2…”

“…All cases described to this point have resulted in squamous cell carcinoma. Although it is unclear how this malignant transformation occurs, factors such as smoking and radiation are thought to play a role 2. No cases of small cell carcinoma in patients treated for JLP have previously been described.…”