High HLA-F Expression Is a Poor Prognosis Factor inPatients with Nasopharyngeal Carcinoma

Background and Aims. In patients with nasopharyngeal carcinoma (NPC), local treatment failure and distant metastasiscontribute largely to poor outcomes. The nasopharynx is an important lymphoid tissue, and NPC tumourigenesis anddevelopment are partly attributed to immune system disorders. Human leukocyte antigen F (HLA-F) has shown a closecorrelation with NPC in many genome-wide association studies (GWASs). However, clinical studies rarely explore therelationship of HLA-F expression with the clinical parameters and outcomes in patients with NPC.Methods. In thisstudy, we used immunohistochemistry to evaluate HLA-F expression in 74 paraffin-embedded NPC tissue sections andthen analysed the association between HLA-F expression and clinical parameters and outcomes. The plasmaconcentration of soluble HLA-F (sHLA-F) in NPC patients and normal controls was also detected, via enzyme-linkedimmunosorbent assay (ELISA).Results. Low, moderate, and high HLA-F expression levels were observed in 47.3% (35/74), 35.1% (26/74), and 17.6% (13/74), respectively, of the tissue samples. HLA-F expression showed a significantcorrelation with local recurrence (p=0037) and distant metastasis (p=0024) and was also an independent factor forlocal recurrence-free survival (LRFS;p=0016) and distant metastasis-free survival (DMFS;p=0004). Although the meanconcentration of plasma sHLA-F in the NPC patients was higher than that in the normal controls (13.63 pg/ml vs.10.06 pg/ml), no statistical significance was observed (p=0118).Conclusions. Our study provides thefirst evidence thathigh HLA-F expression is associated with NPC local recurrence and distant metastasis and may be regarded as a poorprognostic factor for NPC patients. Additional studies using larger sample sizes may be necessary to determine whethersHLA-F is a feasible NPC diagnostic indicator.