Pathology and immunohistochemistry
Thirty-nine (53.4%) patients had a non-keratinizing undifferentiated (WHO- 3 classification) on their pathological examination, followed by 32 (43.8%) patients with non-keratinizing differentiated disease (WHO- 2), and only two patients presented with a keratinizing NPC (2.7%) (WHO- 1). EBER staining for the presence of Epstein Barr Virus (EBV) was positive in 38 samples (52.1%). Proliferation marker Ki-67 was 58.6%±22.7% in our study.