LARYNGEAL CARCINOMA IN A 12-YEAR-OLD CHILD - ASSOCIATION WITH HUMAN PAPILLOMAVIRUS-18 AND PAPILLOMAVIRUS-33

Objective: A laryngeal' squamous cell carcinoma was observed in a 12-y ear-old child. There was no history of preceding papillomatosis or rad iotherapy. We searched for an association with human papillomavirus (H PV). Methods: The resected specimens were assayed for infection with H PV types 11, 16, 18, 31, 33, 35, 39, 42 by in situ hybridization, and for HPV types 6, 16, 18, 33 by Southern blotting. In addition, cervica l swabs of the mother were examined for HPV infection by filter in sit u hybridization. Results: Coinfection by HPV types 18 and 33 could be demonstrated by in situ hybridization, with homogeneous infection of b oth tumor and adjacent epithelial cells by HPV 33 and focal infection of only invasive cancer by HPV 18. Southern blot testing confirmed a h igh viral copy number of HPV 18 DNA. Examination of the mother at the time of tumor diagnosis revealed no evidence of HPV-related lesion in the lower genital tract. Conclusion: In this child, coinfection by at least two HPV types is the only evaluable risk factor for laryngeal ca rcinoma. Coinfection by two HPV types might substitute for carcinogeni c cofactors normally present in adult laryngeal carcinomas.