Immunohistochemical characterization of plasmacytoid dendritic cells in actinic cheilitis and squamous cell Carcinoma of the lower lip

Abstract

Actinic cheilitis (AC) is a potentially malignant disorder affecting mainly the vermilionof the lower lip. Studies indicate that between 3% to 20% of cases of AC can progress tosquamous cell carcinoma (SCC) of the lower lip (SCC-LI). The risk factor associatedwith the pathogenesis of AC is chronic exposure to solar radiation; however, other studiesalso favor the influence of harmful habits (alcohol, smoking). In AC, the detection ofepithelial dysplasia by microscopy is an important prognostic factor; however, the cellularmicroenvironment containing infiltration of immune cells with an anti-tumor or protumor profile, in relation to lip carcinogenesis, needs to be better clarified. In this context,some studies evaluate the presence of dendritic cells (DCs) in AC and SCC-LI; however,the role of plasmacytoid DCs (pDC) in lip carcinogenesis, needs to be better clarified.pDC secrete large amounts of type 1 interferon (IFN-1) in response to viral infection. Inaddition, several studies indicate that pDC, without typifying its maturation stage, are alsoresponsible for participating in immunological mechanisms in the tumormicroenvironment, favoring pro-tumor activities. These mechanisms are unknown in lipcarcinogenesis. Therefore, the objective of the present work is to evaluate the presenceand distribution of pDC, including its maturation stages (mature pDC, CD123+; immaturepDC CD123+/CD303+) in biopsies of AC (n=25) and SCC-LI (n=25), byimmunohistochemical analysis, aiming to better understand its tumorigenic mechanisms,with prognostic and immunotherapeutic implications.