4/26/2001 New England Journal of Medicine Risk of oral cancer can be predicted by the DNA content cells of oral leukoplakia, the most common premalignant lesion of the oral cavity. This finding marks an important advance in the molecular assessment of risk of oral carcinoma in patients with these white patches in their mouths. Such new molecular data have important implications for the standard of care these patients, redefining assessment of the risk and even helping to guide treatment. Oral cancer is the most common neoplasm of the head and neck, with an annual worldwide incidence of new cases exceeding 400,000. However, the five-year survival rate of less than 50 percent has not improved in more than two decades. Risk factors for oral carcinoma have previously been identified. Until now, there have been no reliable predictors of the outcome in individual patients with oral leukoplakia, which may develop into squamous-cell carcinoma. Participants in this study were 150 patients with oral leukoplakia classified as epithelial dysplasia. Researchers measured the nuclear DNA content (ploidy) of the lesions to determine whether DNA ploidy could be used to predict clinical outcome. Patients were followed for a mean of 8.6 years. The DNA content was found to be a powerful predictor of risk of malignant transformation at the site of the lesion. Of the dysplastic leukoplakias, 70 percent were low-risk diploid lesions, three percent of which progressed to cancer, 13 percent were intermediate-risk tetraploid lesions, 60 percent of which progressed to cancer; and 17 percent [...]