RESEARCH ARTICLE Expression of toll-like receptors in HPV-positive and HPV-negative oropharyngeal squamous cell carcinoma—an in vivo and in vitro study Lauri Jouhi 1 & Neeta Datta 2 & Suvi Renkonen 1 & Timo Atula 1 & Antti Mäkitie 1 & Caj Haglund 3 & Abdirisak Ahmed 4 & Stina Syrjänen 5 & Reidar Grénman 6 & Eeva Auvinen 7 & Sanna Lehtonen 2 & Jaana Hagström 8 Received: 29 December 2014 /Accepted: 23 April 2015 # International Society of Oncology and BioMarkers (ISOBM) 2015 Abstract The incidence of oropharyngeal squamous cell car- cinoma (OPSCC) has increased over the past decades in many western countries. This trend is mainly attributed to the human papillomavirus (HPV). Cancer-related actions of immunolog- ical defense systems are being intensively researched. Human toll-like receptors (TLRs) are a family of pattern recognition receptors that participate in the immunological defense against pathogens, but their actions are also linked to cancer. The expression of TLRs in cervical epithelium alters both during the clearance of HPV infection and the HPV-induced neopla- sia, but the expression of TLRs has not been studied in OPSCC. Thirty-five paraffin-embedded, formalin-fixed, squa- mous cell carcinoma tissue specimens were analyzed for TLRs 2, 3, 4, 5, 7, and 9 and HPV and p16 statuses. The TLR 9 expression was lower in HPV-positive tumors com- pared with HPV-negative tumors. TLR 7 was expressed in all cancer specimens, but elevated expression was evident in HPVand/or p16-positive tumors. The majority of p16-positive tumors did not express TLR 5, whereas its expression was stronger in p16-negative tumors. The results of in vitro analysis of five human OPSCC cell lines and one human oral tongue squamous cell carcinoma cell line agree with the in vivo trends: low levels of TLR 5 and high levels of TLR 7 in p16-positive OPSCC. Overall, TLR 7 and 9 expression patterns are demon- strated here to relate to the HPV status in vivo and TLR 5 and 7 expression patterns to the p16 status in vivo and in vitro. Keywords Head and neck cancer . Oropharynx . Carcinoma . HPV . p16 . Toll-like receptor Introduction The incidence of oropharyngeal squamous cell carcinoma (OPSCC) has increased over the past decades in many western countries [1–4]. Specifically, the incidence of palatine tonsil and base of tongue squamous cell carcinomas (SCCs) has increased, whereas in other oropharyngeal subsites, the * Lauri Jouhi lauri.jouhi@helsinki.fi 1 Department of Otorhinolaryngology—Head and Neck Surgery, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 4C-4E, P.O. Box 220, FI-00029 Helsinki, Finland 2 Department of Pathology, University of Helsinki, Haartmaninkatu 3, P.O Box 21, FI-00014 Helsinki, Finland 3 Department of Surgery, University of Helsinki and Helsinki University Hospital, Tukholmankatu 8 B, P.O. Box 20, FI-00014 Helsinki, Finland 4 Department of Oral and Maxillofacial Diseases, University of Helsinki, Haartmaninkatu 8, P.O. Box 700, FI-00029 Helsinki, Finland 5 Department of Oral Pathology, Institute of Dentistry, Faculty of Medicine and MediCity Research laboratory, University of Turku, Lemminkäisenkatu 2, FI-20520 Turku, Finland 6 Department of Otorhinolaryngology—Head and Neck Surgery and Department of Medical Biochemistry, Turku University Hospital, University of Turku, Kiinamyllynkatu 4-8, P.O. Box 52, FI-20521 Turku, Finland 7 Department of Virology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 3, P.O. Box 21, FI-00014 Helsinki, Finland 8 Department of Pathology and Oral Pathology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 3, P.O. Box 21, FI-00014 Helsinki, Finland Tumor Biol. DOI 10.1007/s13277-015-3494-z