Overview of Kaplan-Meier curves for several investigated genetic markers in 89 OL samples. On the y-axis the fraction remaining free of malignant transformation over time is shown. The x-axis shows the time in years. The table below the figure specifies the number of patients at risk at the indicated timepoints for the corresponding groups. (A) Kaplan-Meier curves for presence of at least one CNA and four significant chromosome regions. (B) Kaplan-Meier curves for the presence of at least one mutation and one significantly affected gene, TP53. CNA = Copy number aberration. HR = Hazard ratio.
ARTICLE ABSTRACT
Oral leukoplakia is the most common oral potentially malignant disorder with an annual malignant transformation 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.
We investigated a retrospective cohort of 89 oral leukoplakia patients, and analyzed their oral leukoplakia lesions for the presence of genomic copy-number alterations and mutations in genes associated with oral squamous cell carcinoma.
In 25 of 89 (28%) patients, oral squamous cell carcinoma developed during follow-up. Seventy-nine of 89 (89%) oral leukoplakias harbored at least one genetic event. Copy-number alterations 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.
We provide an extensive description of genetic alterations in oral leukoplakia and its relation to malignant transformation. On the basis of our data we provide a model for the prediction of malignant transformation of oral leukoplakia using dysplasia and genetic markers.
