CD1a+and CD83+Langerhans cells are reduced in lower lip squamous cell carcinoma

Background Actinic cheilitis (AC) is a potentially malignant lesion diagnosed in the lip of patients chronically exposed to the sun that may give rise to a fully invasive lower lip squamous cell carcinoma (LLSCC). It is known that ultraviolet radiation causes dendritic cells (DCs) depletion in the epidermis, but the role of this cellular population in lip cancer progression remains uncertain. Therefore, this study investigated the distribution of DCs in normal, dysplastic and neoplastic tissues of the lower lip. Methods Thirteen cases of lower lip mucocele, 42 of ACs and 21 of LLSCC were retrieved and original diagnoses confirmed by two oral pathologists, who further classified ACs as low- and high-risk lesions. Immunoreactions against CD1a and CD83 identified immature and mature DCs, respectively. Results Immature CD1a+ Langerhans cells (LCs) were significantly decreased in LLSCC when compared to morphologically normal (P 0.05), but ACs demonstrated a lower concentration of CD1a+ LCs than normal epithelium (P 0.05). Conclusion These results suggest that depletion of epithelial LCs, but not IDCs in the connective tissue, would represent an important step for lip cancer development.