Expression of Fas ligand in patients with evident skull base involvement of nasopharyngeal carcinoma

We investigated whether skull base involvement in patients with nasopharyngeal carcinoma (NPC) is correlated with expression of Fas ligand (FasL) in NPC cells. A prospective assessment of FasL expression was determined by immunohistochemistry and in situ hybridization in 98 patients with newly diagnosed NPC. Among these patients, 21 had evident skull base involvement. Expressions of human apoptosis-related genes and FasL were confirmed by reverse transcription-polymerase chain reaction. Relation between the frequency of skull base involvement and FasL expression was analyzed by Chi-square and multivariate analyses. FasL expression was detected in 32 (32.6%) of 98 pathological sections. Compared to patients with low FasL expression in tumors, patients with notable FasL expression had higher incidence of skull base involvement (28.6 vs. 71.4%, p<0.005). Expression of FasL in tumor cells was correlated with the higher frequency of skull base involvement in patients with NPC.