The early detection of precancerous lesions potentially progressing to malignant tumors is critically important to reduce cancer incidence. Epithelial dysplasia has been considered as a reliable histologic hallmark to define premalignant lesions. But the subjectivity of evaluating the degree of epithelial dysplasia and the fact that the degree of epithelial dysplasia may not directly correlate to the rate of malignant transformation, make it more complicated to predict the risk of malignant transformation of precancerous lesions.
This study aimed to evaluate the usefulness of Cyclin D1 expression as a predictable biomarker in oral leukoplakia with and without malignant transformation. This study used 25 cases of oral leukoplakia without malignant transformation and 10 cases with malignant transformation, which were examined at the Department of Oral Pathology, Yonsei University College of Dentistry and were clinically followed up more than 2 years. Monoclonal Cyclin D1 antibody was applied for immunohistochemical study.
The results were as follows:
1. Cyclin D1 experssion was shown in 5 out of 25 cases(20%) of the leukoplakia without malignant transformation, and 8 out of 10 cases(80%) of leukoplakia transformed to squamous cell carcinoma.
2. Cyclin D1 was detected in 11 out of 22 cases(50%) showing epithelial dysplasia, while only 2 out 13 cases(15%) without epithelial dysplasia showed Cyclin D1 expression.
3. Malignant transformation occurred in 10 out of 22 cases with epithelial dysplasia. 20% of mild epithelial dysplasia and all of moderate to severe epithelial dysplasia were transformed to squamous cell carcimoma.
4. There was female prevalence of malignant transformation, and the most frequent site of malignant transformation was tongue.
These results suggest that Cyclin D1 expression appeared to be a predictable biomarker assessing the risk of malignant transformation in oral precancerous lesions.