Abstract 659: Expression patterns of NF-κB in inflammatory oral potentially malignant lesions
Authors: Lin Iris , Zhang Lewei , Rosin Miriam , Rock Leigha , Laronde Denise 
Published: August 2019

Introduction: Oral lichen planus (OLP), a common chronic autoimmune inflammatory condition, is recognized as a potentially malignant condition by the World Health Organization. However, some argue that only OLP with epithelial dysplasia - termed lichenoid dysplasia (LD) - have malignant potential. As research continues to characterize the immune microenvironment of OLP, there is a need to elucidate factors favorable for malignant change. Recent research has demonstrated that activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is key to cancer development. This transcription factor has been extensively explored in inflammation-associated cancers, such as colon and gastric cancers. There is a need to investigate these factors in oral potentially malignant lesions (OPML), including OPL. In this study, we aim to compare clinical and risk habit differences between OLP and LD, and determine if NF-κB expression is associated with histological and clinical features of OPML indicative of cancer risk.

Methods: Clinical, demographic, and histological data have been collected from the Oral Cancer Prediction Longitudinal (OCPL) study and the CoPath Vancouver Coastal Health Database. Patients with a primary diagnosis of OLP or low-grade LD were eligible to participate. Patients with previous history of head and neck cancer, or who have less than one year of follow-up are excluded from enrollment. Demographic, risk habit and clinical information was collected.For completed cases, immunohistochemistry (IHC) has been performed on formalin-fixed and paraffin-embedded tissue. Nuclear reactivity of NF-κB in the epithelium was counted in 10 high-power fields, and cytoplasmic positivity classified into 4 categories. Chi-squared tests were performed on categorical demographic and risk habit data.

Results: To date, 51 participants have been recruited into this ongoing study: 37 with OLP and 14 cases of LD. There is no significant difference in gender and age between groups (p=0.297, p=0.120, respectively). Ever smokers and lesion location at a high-risk site were significantly associated with a diagnosis of LD compared to OLP (p=0.002, p&lt;0.001, respectively). Preliminary IHC results show strong NF-κB positivity in the sub-epithelial lymphocytic infiltrate and strong to moderate cytoplasmic reactivity in the epithelium. Nuclear reactivity appears to increase from lichen planus to dysplasia.

Conclusion: Patients with LD were more apt to be smokers, and more often presented with lesions at a high-risk site compared to those with OLP. Strong NF-κB cytoplasmic positivity in OLP, especially adjacent to areas with intense cytotoxic inflammatory infiltrate, reinforces the prominent role of NF-κB in inflammation.

Citation Format: Iris Lin, Lewei Zhang, Miriam Rosin, Leigha Rock, Denise Laronde. Expression patterns of NF-κB in inflammatory oral potentially malignant lesions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 659.