www.scholarsresearchlibrary.com t Available online a Scholars Research Library Archives of Applied Science Research, 2015, 7 (2):20-24 (http://scholarsresearchlibrary.com/archive.html) ISSN 0975-508X CODEN (USA) AASRC9 20 Scholars Research Library Expression of toll-like receptors in squamous cell carcinoma of the tongue Farzaneh Pakdel 1 , Firouz Pouralibaba 1 *, Sina Pakdel 2 , Reza Khorshidi Khiyavi 3 , Parisa Falsafi 1 , Hosein Eslami 1 , Vahid Fakhrzadeh 4 , Shiva Solahaye Kahnamouii 5 1 Department of Oral Medicine, School of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran 2 Legal Medicine Organization, Tabriz, Iran 3 Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran 4 Department of Protedentics, School of Dentistry, Tabriz University of Medical Science, Tabriz, Iran 5 Neuroscience Research Center, Department of Maxillofacial Surgery, Cardiovascular Research Center, and Drug applied research center, Tabriz University of Medical Science, Tabriz, Iran. _____________________________________________________________________________________________ ABSTRACT To determine of the expression of Toll-like receptor (TLR) 2, TLR4, TLR7 and TLR8 in Oral squamous cell carcinoma (OSCC). Reverse transcription-polymerase chain reaction and Flow cytometry were used to analyze the expression of TLR2, TLR4, TLR7 and TLR8 mRNA and protein in samples from 50 cancer patients consisting of both tumor and normal tissue. This study was done in Tabriz medical University between 2011 till 2013. A significant increase in TLR2, TLR4, TLR7 and TLR8 mRNA levels was detected in OSCC samples. Tumors exhibited high TLR protein expression, (70.1%, 72.4%, 66.7% and 78.2% for TLR2, TLR4, TLR7 and TLR8, respectively, P < 0.05). Nevertheless, a significant percentage of tumors also exhibited TLR4 expression in mononuclear inflammatory cells (48.3%).Tumors with high TLR2 expression in tumor cells or high TLR4 expression in mononuclear inflammatory cells were significantly associated with a higher probability of lymph node metastasis and increased depth of invasion. However, tumors with high TLR8 expression in fibroblast-like cells were associated with low probabilities of invasion and metastasis. There was no significant variation between the expression of TLR2, TLR4, TLR7 and TLR8 among different ethnic groups. TLR2, TLR4, TLR7 and TLR8 expression appears important to the biological pathogenesis of ESCC. TLRs may represent therapeutic targets for OSCC. _____________________________________________________________________________________________ INTRODUCTION Oral cancer or mouth cancer, [1] a subtype of head and neck cancer, is any cancerous tissue growth located in the oral cavity. [2] It may arise as a primary lesion originating in any of the oral tissues, by metastasis from a distant site of origin, or by extension from a neighboring anatomic structure, such as the nasal cavity. Oral or mouth cancer most commonly involves the tongue. It may also occur on the floor of the mouth, cheek lining, gingival (gums), lips, or palate (roof of the mouth). Most oral cancers look very similar under the microscope and are called squamous cell carcinoma, but less commonly other types of oral cancer occur, such as Kaposi's sarcoma. Oral squamous cell carcinoma (OSCC) is the sixth most prevalent malignancy worldwide and accounts for approximately 8–10% of all cancers in Southeast Asia [3] . The prognosis of OSCC remains dismal because more than 50% of patients die from this disease or complications within 5 years with current therapies [4] . Therefore, an improved comprehension of the cellular and molecular mechanisms which initiate tumorigenesis or promote cancer progression, was pursued to bring forth future progress of medical treatment of OSCC. The prognosis of human oral squamous cell carcinoma