MUC1 gene polymorphism does not explain the different incidence of gastriccancer in Portugal and Denmark

MUC1 is a highly polymorphic mucin type glycoprotein expressed on the surfa ce of many epithelial including gastric mucosa, and is present in several b ody fluids and mucous secret ions. A genetic polymorphism due to variation in length of a 60 bp tandemly repeated sequence domain constitutes more tha n half of the coding region of the glycoprotein. We demonstrated previously in a Portuguese population sample that the frequency of small MUC1 alleles is increased in patients with gastric carcinoma, suggesting that the posse ssion of small MUC1 alleles confers increased risk for gastric carcinoma de velopment. This finding raised the possibility that the very high prevalenc e of gastric carcinoma in Portugal could be partly due to a high frequency of small MUC1 alleles in the Portuguese population. In the present study we compared the MUC1 allele distribution in a population of Danish blood dono rs with the distribution in a population of Portuguese blood donors. The fr equency of small MUC1 alleles was significantly higher in the Danish than i n the Portuguese sample, thus failing to lend support to the hypothesis tha t a relatively higher frequency of the small MUC1 alleles might account for the high prevalence of gastric carcinoma in Portugal when compared to Denm ark.