한국인 코인두암종의 조직병리학적 유형 및 EBV 출현율

Histopathologic Types and EBV Prevalence in Nasopharyngeal Carcinomas of Koreans

Background and Objectives：Nasopharyngeal carcinoma(NPC) shows a distinct geographic and demo-graphic distribution with high incidences in Chinese and Southeast Asians. Current WHO classification divides NPC into nonkeratinizing carcinoma(NKC)(differentiated and undifferentiated subtypes), keratinizing squa-mous cell carcinoma(KSCC), and basaloid squamous cell carcinoma(BSCC). Relative frequency of histologic subtypes of NPC is known to vary according to the incidence of NPC. Korea is one of the low-incidence coun-tries according to the GLOBOCAN 2008 database by IARC. The aim of this study is to assess the histopatho-logic types and EBV status of NPC of Koreans. Materials and Methods：We reviewed and reclassified 168 cases of NPC(132 males and 36 females) diagnosed from January 1996 through July 2006. In situ hybridiza-tion for EBV-encoded early RNA(EBER) was performed on 146 cases and the results were compared among different histologic types, genders, and age and stage groups. Results：NKC, undifferentiated subtype(NKC-U) was identified in 106 cases(63.1%) and differentiated subtype(NKC-D) in 49 cases(29.2%). Remaining 13 cases(7.7%) were classified as KSCC. NKC and NKC-U were more common in females than in males. EBV prevalence was higher in NKC than in KSCC(NKC-U, 90% ;,NKC-D, 84.1% ; KSCC, 7.7%) and more com-mon in younger age(≤40) than older age(＞40) group. Conclusion：Histologic type distribution and EBV prevalence of NPC in Korean patients corresponded to that of intermediate incidence area. Pathogenesis of na-sopharyngeal KSCC is assumed to be different from that of NKC.