Unusual anodic migrating isoamylase differentiates selected malignant from nonmalignant ascites.

Ascitic fluid from nine patients with nonmalignant ascites and nine patients with malignant ascites was subjected to isoamylase analysis. Unusual isoamylase bands that migrate to the anode were demonstrated in seven of eight patients with ovarian carcinoma and in one patient with gastric carcinoma. In no case of nonmalignant ascites was anodic isoamylase found, despite the presence of normal amylase in all samples. This is the first report of anodic isoamylase from ascitic fluid in gastric carcinoma and the first series comparing isoamylase patterns in malignant and nonmalignant ascites. Anodic isoamylase on electrophoresis of ascitic fluid may prove to be useful as a tumor marker in differentiating selected malignancies from nonmalignant ascites.