Evaluation of sensitive PDN-21 (katacalcin) determination as tumor marker in medullary thyroid carcinoma.
PDN-21 (katacalcin), a peptide from the calcitonin (CT) gene, was measured in plasma from healthy persons and patients with medullary thyroid carcinoma (MTC). PDN-21 was detectable (greater than or equal to 10 ng/l) in 73% of normal persons (n = 40). In 17 normal persons with undetectable basal plasma levels, PDN-21 became detectable (greater than or equal to 10 ng/l) by stimulation with iv pentagastrin in 7 cases. Basal levels were more often detectable in men than in women. In 65 patients with MTC, PDN-21 levels were highly correlated with CT levels as determined by an "in house" RIA (r = 0.99); the mean ratio of CT/PDN-21, on a molar base, was 0.96 +/- 0.33 over the entire range. In iv stimulation tests with pentagastrin, PDN-21 and CT showed good parallelism (mean ratio of CT/PDN-21: 1.1 +/- 0.62); in MTC patients with normal basal levels, however, peak to basal ratios during iv pentagastrin testing were higher for PDN-21 than for CT, due to the more sensitive PDN-21 assay. In a selective venous catheter study of a patient with MTC, the mean CT/PDN-21 ratio for all samples was 1.04 +/- 0.12, but the peak to peripheral levels were higher for PDN-21 (4.1-fold) than for CT (2.8-fold). In conclusion, determination of PDN-21 by RIA is equivalent to determination of CT in diagnosing MTC patients. In few patients, it might be even slightly more sensitive. PDN-21 should be determined in all cases with borderline CT results.
Blind
E
E
Department of Internal Medicine I, Endocrinology and Metabolism, University of Heidelberg, Germany.
Raue
F
F
Klaiber
T
T
Zink
A
A
Schroth
J
J
Buhr
H
H
Ziegler
R
R
D014408:Biomarkers, Tumor / Q000097:blood*; D002116:Calcitonin / Q000097:blood*; D002277:Carcinoma / Q000097:blood* / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D010418:Pentagastrin / Q000378:metabolism; D010446:Peptide Fragments / Q000097:blood*; D011863:Radioimmunoassay; D013268:Stimulation, Chemical; D013964:Thyroid Neoplasms / Q000097:blood* / Q000175:diagnosis
D014408:Biomarkers, Tumor; D010446:Peptide Fragments; C037553:katacalcin; D002116:Calcitonin; D010418:Pentagastrin