SMAD4 and gastric carcinoma: In particular, van Rees et al. reported that allelic loss of chromosome 18q (involving SMAD4 locus) was significantly less frequent in EBV-positive gastric carcinomas than in EBV-negative gastric carcinomas, which might be compensated for by a higher frequency of gene inactivation through promotor hypermethylation in EBV-positive gastric carcinomas [57].