| Research Abstract |
We have investigated the expression of p27^<Kip1> in oral squamous cell carcinomas (OSCCs) using immunohistochemistry and have tried to investigate the relationship between each expression level and clinico-pathological characteristics such as tumor grade, T, N, stage classifications, effect and outcome. High levels of p27^<Kip1> expression were significantly related to well differentiated cases(p<0.05), NO cases (p<0.01), non advanced cases (p<0.01), and good effective cases (p<0.05). Five-year survival rate of p27^<Kip1> high expression cases was 63.3%, and it was significantly high than that of p27^<Kip1> low expression cases (45.5%) (p<0.05). By Cox's proportional hazards model, high levels of p27^<Kip1> expression significantly made the rate of death decrease. These results suggested that p27^<Kip1> protein expression may be closely related to tumor grade, inhibition of metastasis, effect and outcome, and an useful prognostic marker. Next, we have constructed p27^<Kip1> expression vectors with pcDNA3.1 (stratagene). Moreover, we transfected them to OSCC cell line (B88) in sense or anti-sense oriented, and tried to regulate the p27^<Kip1> gene in B88 cells. Overexpression of p27^<Kip1> in B88 cells (B88/Tp27sense) inhibited the growth, invasion and metastasis of them. Contradictory, low expression of p27^<Kip1> in B88 cells (B88/Tp27anti-sense) promoted the growth, invasion and metastasis. On tumor differentiation, we could detect the morphological change from squamous cell type to spindol cell type in B88/Tp27anti-sense though we could not detect the difference between parental B88 and B88/Tp27sense by HE staining. Moreover, we could detect the induction of involucrin and keratin 7,8 (Cam 5.2) in B88/Tp27sense immunohistochemically. These results suggested that p27^<Kip1> might be related to terminal differentiation of OSSC.
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