Immunocytochemical study of pyruvate kinase isoenzymes in normal and pathologic human liver.
In healthy human livers, L pyruvate kinase (L PK) was detected by immunofluorescence and double labelling in hepatocytes and M PK was detected in bile duct epithelial cells. Numerous associations between isoenzyme type and hepatological lesion were observed. In 10 cases of ethanolic cirrhosis, L and M PK were simultaneously observed in the hepatocytes of regenerative nodules, as they were in biliary neoductules; fibrotic regions were L and M PK negative and the hepatocytes in the anastomosing plate system were almost exclusively L PK positive, as in normal subjects. In 12 hepatocarcinomas, cancer cells had a double L and M specificity with variations in the intensity of the M isoenzyme, while the stroma reaction was L and M negative. In five hepatoblastomas, the simultaneous presence of L and M PK was also observed, but the consistently marked intensity of M PK argues in favour of the embryonic nature of this type of cancer. The results suggest that mature, highly differentiated cells exclusively and specifically synthesize one isoenzyme. A double specificity in pathology reflects the dysfunctional state of the hepatic and biliary epithelial cells or a dedifferentiated state which may terminate with the appearance of a cancer.
D000328:Adult; D001652:Bile Ducts / Q000201:enzymology; D006528:Carcinoma, Hepatocellular / Q000201:enzymology*; D002648:Child; D002675:Child, Preschool; D005455:Fluorescent Antibody Technique; D006801:Humans; D007223:Infant; D007527:Isoenzymes / Q000032:analysis*; D008099:Liver / Q000201:enzymology*; D008104:Liver Cirrhosis, Alcoholic / Q000201:enzymology*; D008113:Liver Neoplasms / Q000201:enzymology*; D008115:Liver Regeneration; D011770:Pyruvate Kinase / Q000032:analysis*
D007527:Isoenzymes; D011770:Pyruvate Kinase