1. Academic Validation
  2. Development of a highly sensitive and specific carboxy-terminal human pancreastatin assay to monitor neuroendocrine tumor behavior

Development of a highly sensitive and specific carboxy-terminal human pancreastatin assay to monitor neuroendocrine tumor behavior

  • Pancreas. 2010 Jul;39(5):611-6. doi: 10.1097/MPA.0b013e3181c68d7a.
Thomas M O'Dorisio 1 Siegfried R Krutzik Eugene A Woltering Erika Lindholm Saju Joseph Abby E Gandolfi Yi-Zarn Wang J Phillip Boudreaux Aaron I Vinik Vay Liang W Go James R Howe Thor Halfdanarson M Sue O'Dorisio Gregg Mamikunian
Affiliations

Affiliation

  • 1 Department of Internal Medicine, University of Iowa Hospitals & Clinics, Iowa City, IA, USA. Thomas-odorisio@uiowa.edu
Abstract

Objective: Pancreastatin is a fragment of the chromogranin A (CgA) molecule. Existing pancreastatin assays, which depend on Antibodies that cross-react in varying percents with the larger prohormone, may lack sensitivity and specificity to detect small changes in neuroendocrine tumor volume.

Methods: We developed a highly specific, sensitive pancreastatin assay. The antibody used recognizes the carboxyl terminal of the peptide hormone and was raised against a 17-amino acid porcine pancreastatin fragment with high homology with the carboxy-terminal Amino acids 286-301 of the human CgA.

Results: Our assay measures more than 95% of circulating pancreastatin levels; has little or no cross-reactivity with CgA, even at plasma concentrations of 1000 ng/mL; and can detect pancreastatin levels of 17 pg/mL. Interassay reproducibility for the pancreastatin radioimmunoassay was determined from results of 3 quality control pools in 15 consecutive assays. Coefficients of variation for low, medium, and high pancreastatin levels were less than 20%. The sensitivity of serial pancreastatin assays to detect early liver tumor activity was demonstrated in 2 patients with slowly progressive neuroendocrine tumors and in patients undergoing surgical cytoreduction.

Conclusions: This highly specific, sensitive pancreastatin assay can detect small changes in liver tumor progression and is up to 100-fold more sensitive and specific than CgA assays in the United States.

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