ABSTRACT
EBV is associated with a high number of tumours and non-tumourous conditions. The rare lymphoepithelioma like carcinoma of the stomach,--just as similar tumours of foregut origin (thymus, lung, salivary gland)--are frequently EBV genom positive with the expression of only a few genes (EBV nuclear antigen 1, EBV encoded ribonucleoproteins/EBER/, latency I). On the basis of the clinicopathological analysis of two cases and literature data the authors point out the male predominance and the relatively favourable prognosis of the patients, furthermore the frequent cardial-subcardial localization of these tumours. Since the frequent non-lymphoepithelioma like stomach tumours,--adenocarcinomas,--show EBV genom positivity in about 1% of the cases, it is concluded that the characteristic lymphoepithelioma like histological pattern is not a sine qua non condition of EBV genom positivity. It may also be assumed, that the CD8 and TIA 1 cytotoxic lymphocytes are not virus but tumour cell specific, however not efficient, perhaps not activated. The low level of apoptotic tumour cells supports this assumption. In one of the cases a double tumour, a genom positive lymphoepithelioma like carcinoma and a genom negative adenocarcinoma, adjacent to each other was seen which speaks in favour of common carcinogenetic factors and shows that microscopic neighbourhood is not a necessary condition in viral association. The origin of the possible oncogenic effect of EBV in the absence of the transforming gene products latent membrane protein 1 and EBNA 2 in genom positive stomach carcinomas is uncertain. The significance of the presence in both cases of CD 5+ tumour cells is not clear, the study of further cases is indicated.
