Evaluation of aryl hydrocarbon receptor expression in oral squamous cell carcinoma and normal oral mucosa using western blot

BACKGROUND: Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that acts as a binding site for toxic chemicals, particularly the dioxin group of chemicals. Elevated levels of AHR have been observed in various human cancers, including lung carcinomas, hepatic carcinomas and in mammary tumors. However, the expression of AHR in oral squamous cell carcinoma (OSCC) patients who are tobacco users are less explored. AIMS AND OBJECTIVES: The aim of the present study is to evaluate and compare AHR levels in OSSC patients and in normals using Western blot technique in an attempt to explore the possible role of AHR in oral carcinogenesis. MATERIALS AND METHODS: The study sample consisted of ten oral squamous cell carcinoma cases which were diagnosed clinically and confirmed histopathologically as OSCC and four samples of the normal oral mucosa. AHR protein expression was evaluated using Western blot technique and chemiluminescence detection kit. The densitometry was performed on a Microtek scan maker MSP flatbed scanner and quantified using Image J software. Mean AHR protein levels were calculated and compared between OSCC and normal oral mucosa using Student's t-test. RESULTS: The mean AHR protein level in OSCC samples (n = 10) was 2878.90 ± 1231.27 and 975.75 ± 227.27 in the normal oral mucosa (n = 4). The OSCC samples showed significantly higher levels of AHR protein compared to the normal oral mucosa (P = 0.008). CONCLUSION: The study showed a significantly higher expression of AHR in oral squamous cell carcinoma samples when compared to the normal oral mucosa, suggesting a possible role of AHR in the initiation, promotion and progression of oral squamous cell carcinoma.