Human papillomavirus may be common within nasopharyngeal carcinoma of Caucasian Americans: investigation of Epstein-Barr virus and human papillomavirus in eastern and western nasopharyngeal carcinoma using ligation-dependent polymerase chain reaction.

BACKGROUND

Nasopharyngeal carcinoma (NPC), particularly those tumors endemic to the Far East, commonly harbor Epstein-Barr virus (EBV), thought to serve as an important oncogenic promoter. Human papillomavirus (HPV) is associated with a proportion of upper aerodigestive tract carcinomas. We hypothesized that HPV might also contribute to the pathogenesis of NPC, and we queried whether geographic and racial distinctions may be identified between NPC of the Far East versus those diagnosed in Caucasian American patients with regard to the interrelationship of histologic subtype and viral infection.

MATERIALS AND METHODS

Formalin-fixed paraffin-embedded tissue (FFPET) from 30 patients (6 Caucasian Americans, 1 Chinese American, 14 and 9 patients from Korea and China, respectively) were studied using the ligation-dependent polymerase chain reaction (LD-PCR). These cases were histologically classified according to the World Health Organization (WHO) schema for NPC. Consensus target probes complementary to the L1 region of over 30 HPV types, as well as target probes complementary to EBER-1 (EBV-related nontranslated latency-associated RNA), were used to amplify target sequences.

RESULTS

Seven of 30 NPC (23%) contained HPV sequences. There were 6 Caucasian American patients with NPC; 3 cases (50%) were HPV positive (HPV+). Two of these Caucasian Americans had WHO type I tumors: one was HPV+ and EBV negative (EBV-) and the other was HPV-/EBV+. The remaining Caucasian American NPCs were WHO-II/III tumors which tested as follows: two were coinfected with HPV and EBV, the other two contained EBER but not HPV sequences. The single Oriental American patient had a WHO-III NPC which was HPV-/EBV+. Of the Eastern NPC patients, 4 (1 WHO-I, 3 WHO-II/III) of 23 (17%) NPCs contained HPV sequences as well as EBV. Conclusion. Human papillomavirus appears to be uncommonly (17%) associated with NPC in patients from the Far East and was detected more often (50%) in NPC from American Caucasian patients. Some of these tumors conformed to our perceptions and expectations of NPC (eg, WHO-I tumors being EBV-/HPV+ and WHO-III tumors being EBV+/HPV-), but other tumors did not conform to these expectations (eg, WHO-III NPC occasionally harboring both HPV and EBV). There appears to be a broad profile in the relationship between HPV, EBV, and NPC histologic subtype. Unfortunately, the number of American Caucasian cases studied are too small to allow for strong conclusions.