RÉSUMÉ
BACKGROUND: CA 19-9, a tumor marker for pancreatic cancer, was reported to be related to the Lewis phenotype. ABO and Lewis antigen are thought to influence the colonization and inflammatory reaction of H. pylori infection. Therefore, we investigated the possible clinical utilization of Lewis blood antigen in characterizing cancer patients by retrospectively evaluating 396 cancer patients' laboratory data. METHODS: Distribution of Lewis blood phenotype of the cancer patients, possible correlation between the Lewis phenotype on erythrocytes and the serum IgG antibody for H. pylori, between the Lewis phenotype on erythrocytes and the level of serum CA 19-9, between Lewis blood phenotype and ABO blood group, and between ABO blood group and serum IgG for H. pylori were investigated. RESULTS: In total 396 cancer patients, the Lewis blood phenotype of Le(a+b-), Le(a-b+), Le(a-b-), and Le(a+b+) occupied 23%, 55.1%, 19%, and 3%, respectively. Patients with Lewis phenotype of Le(a-b-) showed the lowest sero-positive rate of the serum IgG antibody for H. pylor. In 20 stomach cancer patients, 1 out of 8 Le(a+b-) patients showed change in the phenotype to Le(a-b-) and 2 out of 10 Le(a-b+) patients showed change to Le(a-b+) before and after the operation. In 11 pancreatic cancer patients, the frequency of Le(a-b-) was relatively high (36.4%). In 3 out of 4 Le(a-b-) patients, increase in serum CA 19-9 level was noticed. The frequency of Le(a-b+) phenotype in each ABO blood group was higher than any other Lewis phenotypes (O 58.0%, A 53.5%, B 62.3%, AB 46.2%). 8 out of 11 Le(a+b+) patients were blood type O. CONCLUSION: Sero-positive rate of H. pylori was the lowest in Le(a-b-) patients, indicating the possible correlation between low H. pylori infection rate and Le(a-b-) phenotype. Le(a-b-) pancreatic cancer patients showed significant increase in the serum CA 19-9 level. Most Le(a+b+) patients have blood type O. The ABO blood group and serum IgG for H. pylori did not show any significant correlation.