Immunohistochemical Expression of Tazarotene-induced Gene 3 in Oral Squamous Cell Carcinoma

Background: The prognosis of hyperproliferative skin lesions, such as psoriasis, basal cell carcinoma and nonmelanoma skin cancers, is significantly benefited from the levels of Tazarotene-induced gene-1 (TIG3) expression and subsequent treatment with tazarotene. Such observations suggest that TIG3 could be used as a biomarker for apoptosis, differentiation and proliferation. The current study aimed to evaluate the expression of TIG3 in normal oral mucosa (NOM) and oral squamous cell carcinoma (OSCC) compared to normal skin (NS) and skin squamous cell carcinoma (SSCC) using immunohistochemistry.

Methods: Seventeen cases each of SSCC, OSCC, NOM and NS were evaluated. Each section was immunohistochemically stained with a rabbit polyclonal TIG3 antibody. The entire procedure was blinded and evaluated by 5 observers. Statistical analysis was performed using the chi-square test.

Results: There was a significant decrease in TIG3 protein expression in OSCC and SSCC compared to that in NOM and NS (p = 0.008). The progressive loss of expression was observed as the grade of both malignancies increased. However, there was no significant difference in the expression among the normal tissue groups and within SCC groups of similar grades.

Conclusion: The present study suggests that the loss of TIG3 is an important event in carcinogenesis. TIG3 acts as a regulator of keratinocyte proliferation and terminal differentiation. Therefore, TIG3 could be a potential biomarker to differentiate aggressive and nonaggressive neoplasms.

Keywords: Oral Squamous Cell Carcinoma; Tazarotene-induced Gene 3; Transglutaminase-1.