Elucidating the Genetic Landscape of Oral Leukoplakia to Predict Malignant Transformation

Purpose: Oral leukoplakia is the most common oral potentially malignant disorder with an annual malignant trans-formation rate of 1% to 5%. Consequently, oral leukoplakia patients have a 30% to 50% lifetime risk to develop oral squamous cell carcinoma. Although risk factors for malignant transformation of oral leukoplakia have been investigated, no definitive risk stratification model has been proposed. Next -generation sequencing can elucidate the genetic landscape of oral leukoplakia, which may be used to predict the risk for malignant transformation.Experimental Design: We investigated a retrospective cohort of 89 oral leukoplakia patients, and analyzed their oral leuko-plakia lesions for the presence of genomic copy-number altera-tions and mutations in genes associated with oral squamous cell carcinoma. Results: In 25 of 89 (28%) patients, oral squamous cell carcinoma developed during follow-up. Seventy-nine of 89 (89%) oral leuko-plakias harbored at least one genetic event. Copy-number altera-tions were present in 61 of 89 (69%) oral leukoplakias, most commonly gains of chromosome regions 8q24 (46%) and 20p11 (20%) and loss of 13q12 (19%). Mutations were present in 59 of 89 (66%) oral leukoplakias, most commonly in TP53 (28%), FAT1 (20%), and NOTCH1 (13%). Genetic data were combined with the presence of dysplasia to generate a prediction model, identifying three groups with a distinct risk for malignant transformation. Conclusions: We provide an extensive description of genetic alterations in oral leukoplakia and its relation to malignant trans-formation. On the basis of our data we provide a model for the prediction of malignant transformation of oral leukoplakia using dysplasia and genetic markers.