Cancer-associated tumour markers CA 19-9 and CA-50 in patients with pancreatic cancer with special reference to the Lewis blood cell status.

Monoclonal antibodies 19-9 and C-50 were used to assay the cancer associated tumour antigens CA 19-9 and CA-50 in plasma from patients with confirmed pancreatic cancer, and related to the blood group and Lewis blood cell status. The plasma expressions of CA 19-9 or CA-50 were similar, including cases where the patients had Lewis phenotype Le (a-b-). However, analyses of both the tumour antigens could be used to differentiate the presence of cancer from its absence in Le (a-b-) individuals. The findings indicate that the targets for the monoclonal antibodies 19-9 and C-50 are similar. The practical implications of these findings are discussed.