456 Analysis of Clinical, Histologic, and Molecular Characteristics of Proliferative Verrucous Leukoplakia

OBJECTIVES/GOALS: This study aims to develop objectively scored histological characteristics of early oral leukoplakia, which may be correlated with molecular pathways predictive of progression into proliferative verrucous leukoplakia (PVL). The secondary aim is to develop a biomarker profile to be used in diagnosis, staging, and management of PVL. METHODS/STUDY POPULATION: Clinical and pathology records of 120 patients with oral leukoplakia and/or PVL were reviewed. Eight patients were selected—all had serial biopsies over time leading to PVL suspicion. Specimens were deidentified and subjected to blinded examination by a board certified oral pathologist, then scored relative to the extent of each of the commonly accepted histologic characteristics of PVL: hyperkeratosis, acanthosis, blunt rete ridges, hyperchromatic nuclei, increased nuclear-cytoplasmic ratio, dyskeratosis, and surface corrugation. Given these results, a larger subset of patient samples will be labeled and assayed for expression of epidermal growth factor receptor tyrosine kinases and downstream pro-oncogenic signaling mediators. Expression of these factors will be tested against progression to PVL. RESULTS/ANTICIPATED RESULTS: Histologically, in scoring the specimens from eight subjects, the characteristics of acanthosis, dyskeratosis, and blunted rete ridges had the strongest correlation with eventual progression to PVL. These criteria will therefore be recommended as an objective histopathologic method of identification of patients with high risk of development of PVL, and therefore malignant potential. We expect the results of the biomarker assay to provide a molecular basis for predicting PVL pathogenesis. Particularly, we anticipate pro-oncogenic targets such as EGFR, PI3K, Akt, and mTOR pathways will show increased expression as leukoplakic lesions progress. These results would then provide the basis for testing patient samples for expression of these markers in a longitudinal study of PVL emergence and progression. DISCUSSION/SIGNIFICANCE: The aggressive nature of PVL, with a rate of malignant transformation of 61% and mortality rate of 40%, requires close clinical monitoring in order to improve patient outcomes. Therefore, well defined objective clinical, histologic, and molecular criteria are critical for early detection of sites likely to progress to PVL and subsequent malignancy.