Henry Ford Hospital Medical Journal


Eighteen cases of medullary thyroid carcinoma (MTC) (11 hereditary) had parallel measurements of basal plasma levels of somatostatin (SRIF), levels of SRIF extracted from fresh tumor tissue (radioimmunoassay), and immunohistochemistry (peroxidase-antiperoxidase method) using an anti-SRIF antibody on paraffin sections. Immunohistochemistry disclosed some cell positivity in nine cases (50%). Plasma levels of SRIF were above normal (> 50 pg/mL expressed in terms of the 14 amino acid SRIF peptide) in only two of 12 patients. Extraction of fresh tumor tissue detected SRIF in 60% of our cases: two patients > l.200pg/mg (equivalents 14). with the other positive values ranging between 13 and 200 pg/mg. In only one case were levels of SRIF concordant between plasma and tumor tissue. However, this type of correlation may be invalid for technical reasons or because of other factors, such as different kinetics for the hormones in tumor and plasma.