IMMUNOHISTOCHEMICAL DETECTION OF PARATHYROID HORMONE-RELATED PROTEIN IN A RARE VARIANT OF HEPATIC NEOPLASM (SCLEROSING HEPATIC CARCINOMA)

Sclerosing hepatic carcinoma represents an uncommon subtype of hepatic malignancy, frequently associated with hypercalcemia. We applied immu nohistochemistry using the avidin-biotin-complex technique to examine the presence of parathyoid hormone-related protein (PTHrP) in formalin -fixed and paraffin-embedded sections of tissue From a case of scleros ing hepatic carcinoma obtained at autopsy. Two polyclonal antibodies a gainst the regions 24 to 35 and 107 to 111 of human PTHrP, and a monoc lonal antibody that recognizes the human sequence 38 to 64 of this pro tein, were used. Preabsortion tests using the corresponding synthetic peptide as antigen were done with these antibodies. The neoplastic tis sue displayed cytoplasmic immunostaining, diffuse with the antibodies against the amino- or carboxy-terminal regions of PTHrP, and with a pr edominant peripheral pattern when using the antibody to the midregion of the molecule. Tumor cells positive for PTHrP were also positive for hepatocellular markers cytokeratins 10, 17, and 18, but negative for chromogranin A. Our findings provide the first evidence for PTHrP prod uction in the sclerosing subtype of hepatic carcinoma. Copyright (C) 1 996 by W.B. Saunders Company.