title: Up-regulation of Fas ligand and down-regulation of Fas expression in oral carcinogenesis.
abstract: An important molecule involved in delivering the death signal that initiates apoptosis is called Fas, or Apo-1, which sits on the cell surface. When another molecule called the Fas ligand (FasL) binds to it, Fas triggers a series of events inside the cell that leads to apoptosis. In order to investigate the mechanism of immune escape and the expression of Fas and FasL in oral premalignant lesions (OPLs) and oral squamous cell carcinomas (OSCCs), a total of 64 samples were evaluated by an immunohistochemical method using a labelled streptavidin-biotin assay. These samples comprised nine hyperkeratotic and 24 oral premalignant lesions (nine of mild, moderate, and six of severe dysplastic lesions), and 24 OSCCs, together with seven healthy controls. The results demonstrated that the majority of invasive OSCCs showed down-regulation of Fas expression but up-regulation of FasL expression. These phenomena were also detected in OPLs. The results indicate that the expression of Fas and FasL is involved in oral carcinogenesis and this may be a mechanism by which the cancer cells evade the host immune assault. Perhaps, in future, Fas/FasL system may be used as a prognostic biomarker in predicting the behavior of oral premalignant lesions.
authors.affiliation: Oral Bio-Science Laboratories, Faculty of Dentistry, The University of Hong Kong, Hong Kong. qchen@khusua.hku.hk
authors.forename: Q
authors.initials: Q
authors.lastname: Chen
authors.forename: L P
authors.initials: LP
authors.lastname: Samaranayake
authors.forename: X
authors.initials: X
authors.lastname: Zhen
authors.forename: G
authors.initials: G
authors.lastname: Luo
authors.forename: M
authors.initials: M
authors.lastname: Nie
authors.forename: B
authors.initials: B
authors.lastname: Li
mesh_terms: D017209:Apoptosis; D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D002681:China; D015536:Down-Regulation; D053222:Fas Ligand Protein; D006801:Humans; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009062:Mouth Neoplasms / Q000378:metabolism*; D015854:Up-Regulation; D019014:fas Receptor / Q000378:metabolism*
chemical_list: C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D019014:fas Receptor