The Epstein-Barr virus-associated gastric carcinoma in Southern and Northern China.

In the present study, we examined the proportions of Epstein-Barr virus-associated gastric carcinomas (EBV-GCs) in Guangzhou, southern China and Shenyang, northern China, two areas differing markedly in nasopharyngeal carcinoma (NPC) incidence. Using in situ hybridization assay, the presence of EBV-encoded small RNA (EBER) was examined in 198, and 180 gastric cancer cases in Guangzhou and Shenyang, respectively. The proportion of EBV-GC in Guangzhou (9%) was significantly higher than that in Shenyang (6%), and the odds ratio (OR) for Guangzhou, after adjusting for the effects of age, sex, and tumor subsite, was 2.7 (95% CI = 1.1-6.2) when Shenyang was taken as reference. There was a male predominance of EBV-GC, and the OR for male was 3.0 (95% CI = 1.2-7.3) when female was taken as reference. We observed a weak and negative age dependence in the proportion of EBV-GC (p-values for trend = 0.077). The EBV-GC was most commonly observed in the middle part of stomach in both series. The frequency of EBV-GCs was higher in cases with p53 overexpression than in cases without p53 expression (OR = 2.4, 95% CI = 1.0-5.8). Among p53-positive cases, the frequency of EBV-GC decreased as the proportion of p53-positive carcinoma cells increased (p for trend = 0.021). In conclusion, the present study suggested that the frequency of EBV-GC in Guangzhou, southern China, where NPC is the most common in the world, may be higher than that in other parts of China.