Composition and production of pancreatic tumor related antigens

Serum increase and liver overexpression of carbohydrate 19.9 antigen in patients with genetic haemochromatosis

CA 19.9 antigen is mainly secreted by biliary and pancreatic duct cells. Its metabolism could be modified in genetic haemochromatosis by iron accumulation within these cells. Therefore, CA 19.9 was assayed in the serum samples of 84 patients with genetic haemochromatosis before and after iron depletion and immunolocalised in the liver of 24 untreated genetic haemochromatosis cases. The study showed that serum CA 19.9 (N < 37 IU/l) was increased (SD) before treatment (41.2 (34)) when compared with after the venesection period (16 (12)), and correlated, before treatment, with the amount of iron excess, transaminases, fibrosis, and biliary iron deposits. Hepatic CA 19.9 was located within the cytoplasm of bile duct and cholangiolar cells. In conclusion, this study shows that a mild, reversible, and non-specific increase in serum CA 19.9 is common in genetic haemochromatosis patients and shows that this increase is related to iron excess, directly or through associated liver damage. The unexplained finding of a mild increase in serum CA 19.9 should lead, in a patient with no diagnosis, to the search for liver iron overload, and, in a patient with untreated genetic haemochromatosis, not to further diagnostic procedures unless this finding persists after completion of the venesection treatment.

Prognostic value of serum CA 19-9 levels in pancreatic adenocarcinoma

Thirty-eight patients with histologically proven pancreatic adenocarcinoma were investigated to establish the utility of serum CA 19-9 as a prognostic indicator. CA 19-9 assays were performed serially during the course of the disease. In four patients with negative Lewis blood type, the CA 19-9 levels remained essentially normal throughout the disease course. In the remaining 34 patients, (1) CA 19-9 levels were significantly lower in patients with tumor size no larger than 5 cm in diameter, and in patients with resectable tumors than in those with tumor size larger than 5 cm or with unresectable tumors (p less than 0.01). 2) CA 19-9 levels dropped sharply after resection in all 11 resectable patients, whereas no significant change was found after laparotomy without resection. (3) The average survival time in seven patients whose CA 19-9 levels returned to normal after resection was significantly longer than in those four patients with postoperative CA 19-9 levels that decreased but did not return to normal (21.9 versus 8.7 months, p less than 0.05). (4) In 6 of 11 patients who underwent resection, recurrent elevation of CA 19-9 preceded changes detectable by computed tomography or clinical examination by 2 to 9 months. (5) In 23 patients who died of pancreatic carcinoma, 15 (65%) had an obvious rise in CA 19-9 level before death. There was a correlation between the doubling time of the CA 19-9 serum level and survival time (r = 0.5, p less than 0.05). Because it can be demonstrated that the reduction of tumor burden by resection lowers serum CA 19-9 levels, serum CA 19-9 levels may be a useful indicator of whether other forms of treatment such as radiation therapy or chemotherapy also reduce the tumor burden.