Prognostic significance of Fas and Fas ligand expressions in human esophageal cancer

Esophageal carcinomas have recently been shown to express Fas ligand (FasL) and down-regulate Fas to escape from host immune surveillance. However, th e prognostic importance of Fas/FasL and their correlation with clinico-path ological characteristics are Set to be delineated in this highly malignant carcinoma. Specimens from 106 esophageal squamous cell carcinoma patients w ere used for immunohistochemical evaluation of Fas, Fast, and CD8 expressio ns, Fifty-two (49%) and 34 (32%) patients were positive for Fast and Fas, r espectively. There were no associations between Fast expression and clinico pathological characteristics except lymph vessel invasion. Strong Fast expr ession correlated with significant (P = 0.0011) decrease in tumor nest CD8 cells. However, neither Fast nor CD8+ had any impact on patient survival. Strong Fas expression was correlated with depth of invasion (40.3% in pT1,T 2 versus 20.5% in pT3,T4; P = 0.0308), histological differentiation (45.7% in well versus 25.4% in nonwell; P = 0.0347), and lymph node metastasis (22 .6% in positive versus 45.5% in negative; P = 0.0129), Fas expression was o ne of the independent favorable prognosticators for patients' survival (ris k ratio, 3.26; P = 0.0103) in esophageal SCC, Fas expression was an indepen dent prognosticator for recurrence-free survival, whereas Fast expression d id not influence the survival in esophageal squamous cell carcinoma. Down-r egulation of tumor Fas may be the hallmark of immune privilege for the tumo r, thus causing the patients' poorer outcome. Tumor Fast may counterattack the host immune cells to such an extent that the prognosis is not affected.