Squamous cell carcinoma (SCC), a cancer of the epithelium, is the most common human cancer throughout the body. When SCC occurs in the oral cavity, the five-year survival rate is less than 50 per cent. Before SCC develops, pre-malignant changes often become visible to patients or clinicians. While this offers the opportunity for early intervention to prevent the progression to cancer, only 15-20 per cent of oral pre-malignant lesions (OPLs) will progress to invasive carcinomas. Currently, it is not possible to determine which lesions will develop into cancer. It may be possible to predict cancer risk by studying the molecular features of OPLs. The progression to cancer is caused by genetic alterations to cells; some changes are the “driver” genetic alterations that lead to cancer, while others are random genetic changes. Determining the specific genetic events that are associated with progression to cancer would help identify those at greatest risk for cancer. Ivy Tsui is studying the initiating genetic events at the pre-malignant stage to identify genetic markers that can predict whether an OPL will become malignant. To do this, she is studying the molecular mechanisms of oral cancer progression. Using DNA from banked samples, she is assessing DNA alterations across the whole genome of late stage OPLs and tumours. Once she has identified recurring alterations, she will compare them with the genomes of early stage OPLs – both those that are known to have progressed to cancer, and those that did not. Once validated, these genetic markers will used to develop a clinical diagnostic tool. If DNA from a patient's OPL can be assessed, patients at risk could be treated early and immediately to prevent progression to cancer. The identified genes critical for oral cancer development could also be used to develop therapeutic targets to treat oral cancer patients.