Abstract
Expanding regions of epithelial dysplasia are often found around oral squamous cell carcinoma (SCC). Failure to resect such regions can lead to local recurrence or a second primary cancer. However, epithelial dysplasia is difficult to distinguish from normal mucosa. Moreover, the border of epithelial dysplasia is difficult to define.
To clearly demarcate the border of expanding regions of epithelial dysplasia surrounding SCC, we used staining with 3% iodine solution to decide the surgical margin. We quantified telomerase activity in tumor, in epithelial dysplasia, and in normal epithelium. We also studied pathological findings. Thirty-one primary cases of oral SCC surrounded by iodine-unstained regions were investigated. Fluorescence-based TRAP was used to quantify telomerase activity. Pathological studies used HE staining, PAS staining, and PAS staining after α-amylase digestion test.
We obtained the following results:
On pathological examination, the iodine-unstained region was recognized as dysplasia of varying degrees around the tumor. In the iodine-unstained region, the higher the degree of dysplasia, the higher was the rate of negative staining for PAS.
Telomerase activity was 52.7U/μgP in SCC, 37.2U/μgP in epithelial dysplasia, and 2.9U/μgP in normal epithelium. When the degree of dysplasia was compared with the telomerase activity, a higher degree of dysplasia was found to be associated with an increase in the telomerase activity.
These results indicate that cells that have already acquired unrestricted proliferative capacity have increased epithelial dysplasia in iodine-unstained regions. Therefore, the epithelial dysplasia should be resected with the SCC. Staining with iodine solution is useful in defining regions of epithelial dysplasia.
