MMPS, TIMP-2, and TGF-β1 in the cancerization of oral lichen planus

Background. Matrix metalloproteinases (MMPs) and transforming growth factor-pi (TGF-beta 1) are important in many physiological and pathological processes. Methods. Immunohistochemistry for MMP-2, MMP-9, membrane-type 1 MMP (MT1-MMP, MMP-14), tissue inhibitor of matrix metalloproteinase (TIMP)-2, and TGF-beta were performed on normal mucosa, nonatrophic oral lichen planus, atrophic oral lichen planus, and oral squamous cell carcinomas (OSCC) resulting from lichen planus. Results. Expression of MMPs progressively increased from normal mucosa to nonatrophic oral lichen planus, atrophic oral lichen planus, and OSCCs. Immunoscores of MMPs in atrophic oral lichen planus was significantly greater than nonatrophic oral lichen planus. Moreover, immunoscore of MMP-9 of OSCCs was significantly greater than both atrophic and nonatrophic lichen planus. Furthermore, expression of TIMP-2 and TGF-beta 1 paralleled increases seen with MMPs. Conclusions. Imbalance between MMPs and TIMPs may be involved in cancerization of oral lichen planus. MMP-2, MT1-MMP, and especially MMP-9 may be useful markers for judging potency of malignant transformation from oral lichen planus. (c) 2008 Wiley Periodicals, Inc.