 The mortality rate of oral cancer in Taiwan is still high with no decrease. One of the reasons result in these situations is the patent visits hospital for treatment in late stage of oral cancer. Recently, the government makes effort in oral cancer screening to find oral potentially malignant disorders OPMD early. However, there is no conscience in treatment strategies of OPMD up to now. In this study, we will set a OPMD data bank, and use the cases to find out the potential biomarker, which is able to predict the oral cancer malignant transformation. Sixty OPMD with oral cancer transformation will be recruited, and 60 OPMD with no oral cancer malignant transformation will also be enrolled as the disease control group. Besides, 20 normal cases and 60 oral cancer cases resulting from previous OPMD will be collected. All those groups will detect the expression of p62SQSTM1 to investigate the possibility that p62SQSTM1 as a biomarker to predict the malignant transformation of OPMM, and a guideline to treat or not to treat OPMD. 