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 non-melanoma 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 with 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 with 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 non-aggressive neoplasms.

Expression of type III collagen correlates with poor prognosis in oral squamous cell carcinoma.

AIM: The aim of the present study was to evaluate, compare, and correlate the types of collagen fibers seen in different grades of oral cancer. METHODS: Thirty cases of histologically-diagnosed, well-, moderately-, and poorly-differentiated oral squamous cell carcinoma (OSCC) were retrieved from the archives of the Institute. Collagen was evaluated using picrosirius red stain and immunohistochemical analysis of the antibody to type III collagen. A correlation between these findings and the grade of OSCC was evaluated. RESULTS: Collagen fibers showed a change in birefringence ranging from reddish-orange to greenish-yellow in well- to poorly-differentiated oral squamous cell carcinoma. The findings were statistically significant for polarizing colors observed in grades of OSCC (P<.001). Immunohistochemical staining intensity of type III collagen changed from weak to strong as grade increased for OSCC, and was also statistically significant (P<.001). CONCLUSION: In the present study, tumor progression reflected a change in collagen present, from type I to type III. Determination of the type of collagen in different grades of OSCC can facilitate therapeutic targeting of molecules responsible for invasion and progression of oral cancer.