Histology-specific gender, age and tumor-location distributions of Epstein-Barr virus-associated gastric carcinoma in Japan.

We examined 1,918 Japanese gastric cancer cases diagnosed during the period 1976-1995 to clarify histology-specific gender, age and tumor-location distributions of Epstein-Barr virus-associated gastric carcinoma (EBV-GC). EBV-GCs accounted for 4.5% and 6.1% of 1,088 intestinal-type and 830 diffuse-type gastric carcinomas, respectively. Both intestinal- and diffuse-type EBV-GCs showed male predominance, but the observed gender difference was statistically significant only in diffuse-type carcinomas (P<0.001). An age-dependent decrease of the EBV-GC proportion was observed in intestinal-type carcinomas (P=0.002), but not in diffuse-type carcinomas. In intestinal-type tumors, the estimated incidence of EBV-GCs reached its peak around age 70. Diffuse-type EBV-GCs appeared to have a much older peak incidence, if any. Both intestinal- and diffuse-type EBV-GCs were least prevalent in the stomach antrum. This study, examining the largest number of EBV-GCs in current literature, showed different patterns of age-dependence in intestinal- and diffuse-type EBV-GCs, suggesting that pathogenic pathways of EBV-GCs may be different in these 2 histological types.