Immunohistochemical Detection of Aurora A and ERK Pathway in Oral Leukoplakia and Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common types of human cancer in the world. Oral leukoplakia (OLK) is the most commonly diagnosed premalignant lesion in the oral cavity and it is also most associated with the development of OSCC. However, the mechanism of malignant transformation from OLK to OSCC is not completely understood. In this study, we attempted to evaluate expression of Aurora A and the main effectors in the Ras/Raf/MEK/ERK pathway in OSCC and OLK clinical tissues. Protein expression was analyzed by immunohistochemical technology in 25 tissue samples of OLK and 21 OSCC clinical tumor specimens. Upon analyzing the levels of Aurora A, phospho-MEK1/2 and phospho-ERK1/2, a remarked increase was observed in tumors compared to OLK tissues. No statistically significant difference between tumor and OLK tissues was found for pRaf-1 S259 and ERK1/2. These results suggest that the increase in Aurora A, phospho-MEK1/2 and phospho-ERK1/2 expression was closely correlated with malignant transformation of OLK. Furthermore, Aurora A, phospho-MEK1/2 and phospho-ERK1/2 might be coordinated for valuable prognostic indicators of malignant transformation of OLK. In addition, more than 50% pERK1/2 immunopositive cells appears to be a good cut off value to predict the malignant transformation of OLK.