Validation of neurokinin a assays in the United States and Europe.

Objectives: International cooperative group trials require specific, sensitive biomarker assays that are validated between continents. Neurokinin A (NKA) has been shown to be a powerful independent predictor of a poor prognosis in well-differentiated midgut neuroendocrine tumors. We hypothesized that NKA concentrations of clinical specimens evaluated in NKA assays in the United States and the United Kingdom would be equivalent, even though assay techniques were significantly different.

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

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.