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Nasopharyngeal carcinoma (NPC) is categorized into three histopathological types based on the degree of differentiation according to the World Health Organization (WHO) classification:keratinizing squamous cell carcinoma(WHO type I),non-keratinizing carcinoma(WHO type II),and undifferentiated carcinoma(WHO type III),among which type I is especially rare at the time of diagnosis before any therapy.