Evaluation of premalignant potential in oral lichen planus using interphase cytogenetics

This study attempted to evaluate whether oral lichen planus (OLP) has the p otential to progress to oral squamous cell carcinoma (OSCC) by comparing th e degree of genetic instability between clinically-curable OLP and lesions that progressed to OSCC. Fifteen cases of steroid-responsive OLP and two ca ses of lichenoid dysplasia (LD) that progressed to OSCC were used for this study. Chromosome in situ hybridization (CISH) was performed for chromosome s 9 and 17. The fraction of polysomic and monosomic cells for chromosome 9 increased in mucosal epithelium compared to those of lymphocytes in OLP. Th is difference was statistically significant (P=0.0017, 0.0054, respectively ). Two LD patients showed 15.38% and 22.58% of PI for chromosome 9. In OSCC that developed from LD, the fraction of monosomic cells for chromosome 9 i ncreased by more than 70%. We concluded that LD should be treated as a high -risk premalignant lesion and strongly suggest that the monosomy of chromos ome 9 may have a critical role in progress to malignancy from LD.