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Definitive Characterization of CA 19-9 in Resectable Pancreatic Cancer Using a Reference Set of Serum and Plasma Specimens.

Haab BB, Huang Y, Balasenthil S, Partyka K, Tang H, Anderson M, Allen P, Sasson A, Zeh H, Kaul K, Kletter D, Ge S, Bern M, Kwon R, Blasutig I, Srivastava S, Frazier ML, Sen S, Hollingsworth MA, Rinaudo JA, Killary AM, Brand RE - PLoS ONE (2015)

Bottom Line: We gained additional information about the biomarker by comparing two distinct assays.The two CA 9-9 assays agreed well in overall performance but diverged in measurements of individual samples, potentially due to subtle differences in antibody specificity as revealed by glycan array analysis.Thus, the reference set promises be a valuable resource for biomarker validation and comparison, and the CA 19-9 data presented here will be useful for benchmarking and for exploring relationships to CA 19-9.

View Article: PubMed Central - PubMed

Affiliation: Van Andel Research Institute, Grand Rapids, MI, United States of America.

ABSTRACT
The validation of candidate biomarkers often is hampered by the lack of a reliable means of assessing and comparing performance. We present here a reference set of serum and plasma samples to facilitate the validation of biomarkers for resectable pancreatic cancer. The reference set includes a large cohort of stage I-II pancreatic cancer patients, recruited from 5 different institutions, and relevant control groups. We characterized the performance of the current best serological biomarker for pancreatic cancer, CA 19-9, using plasma samples from the reference set to provide a benchmark for future biomarker studies and to further our knowledge of CA 19-9 in early-stage pancreatic cancer and the control groups. CA 19-9 distinguished pancreatic cancers from the healthy and chronic pancreatitis groups with an average sensitivity and specificity of 70-74%, similar to previous studies using all stages of pancreatic cancer. Chronic pancreatitis patients did not show CA 19-9 elevations, but patients with benign biliary obstruction had elevations nearly as high as the cancer patients. We gained additional information about the biomarker by comparing two distinct assays. The two CA 9-9 assays agreed well in overall performance but diverged in measurements of individual samples, potentially due to subtle differences in antibody specificity as revealed by glycan array analysis. Thus, the reference set promises be a valuable resource for biomarker validation and comparison, and the CA 19-9 data presented here will be useful for benchmarking and for exploring relationships to CA 19-9.

No MeSH data available.


Related in: MedlinePlus

Glycan array analysis of three CA 19–9 antibodies.Each antibody was incubated at 2 μg/mL on a glycan array containing 610 distinct glycans (glycan array version 5.1 from the Consortium for Functional Glycomics). The graph includes the glycans showing the highest levels of binding by any of the antibodies. For each antibody, we normalized the raw fluorescence values to set the highest value to 1. The list specifies the glycans included in the plot, and the labels above the columns indicate the primary motif in each glycan. DRG is the Assay 1 antibody, 9L426 is the Assay 2 antibody, and M081221 is another anti-sialyl Lewis A antibody included for comparison.
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pone.0139049.g003: Glycan array analysis of three CA 19–9 antibodies.Each antibody was incubated at 2 μg/mL on a glycan array containing 610 distinct glycans (glycan array version 5.1 from the Consortium for Functional Glycomics). The graph includes the glycans showing the highest levels of binding by any of the antibodies. For each antibody, we normalized the raw fluorescence values to set the highest value to 1. The list specifies the glycans included in the plot, and the labels above the columns indicate the primary motif in each glycan. DRG is the Assay 1 antibody, 9L426 is the Assay 2 antibody, and M081221 is another anti-sialyl Lewis A antibody included for comparison.

Mentions: Both antibodies bound the canonical CA 19–9 antigen—sialyl Lewis A—but with differences (Fig 3 and Fig 4). The antibody from Assay 2 (9L426) bound more strongly than the Assay 1 antibody to dimeric sLeA-LeA, as evidenced by the better signal at the low concentration of 0.2 μg/mL, but it showed no binding to the sialic acid variant Neu5Gc. It also bound to sialyl Lewis C (non-fucosylated sialyl Lewis A) at the relatively high concentration of 20 μg/mL. In contrast, the Assay 1 antibody (only the detection antibody was available from the commercial kit) showed greater binding to Neu5Gc but no additional binding to sLeC. A third antibody (clone M081221, Fitzgerald, Acton, MA), not used in Assay 1 or 2 but included for comparison, bound other glycans in addition to those displaying the canonical CA 19–9 antigen. This antibody cross-reacted with glycans containing sialyl Lewis X, an isomer of sialyl Lewis A in which the attachment of the fucose and galactose to the core structure is switched. Thus the CA 19–9 antibodies have overlapping but distinct specificities, including binding to some structures beyond the canonical CA 19–9 antigen.


Definitive Characterization of CA 19-9 in Resectable Pancreatic Cancer Using a Reference Set of Serum and Plasma Specimens.

Haab BB, Huang Y, Balasenthil S, Partyka K, Tang H, Anderson M, Allen P, Sasson A, Zeh H, Kaul K, Kletter D, Ge S, Bern M, Kwon R, Blasutig I, Srivastava S, Frazier ML, Sen S, Hollingsworth MA, Rinaudo JA, Killary AM, Brand RE - PLoS ONE (2015)

Glycan array analysis of three CA 19–9 antibodies.Each antibody was incubated at 2 μg/mL on a glycan array containing 610 distinct glycans (glycan array version 5.1 from the Consortium for Functional Glycomics). The graph includes the glycans showing the highest levels of binding by any of the antibodies. For each antibody, we normalized the raw fluorescence values to set the highest value to 1. The list specifies the glycans included in the plot, and the labels above the columns indicate the primary motif in each glycan. DRG is the Assay 1 antibody, 9L426 is the Assay 2 antibody, and M081221 is another anti-sialyl Lewis A antibody included for comparison.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4592020&req=5

pone.0139049.g003: Glycan array analysis of three CA 19–9 antibodies.Each antibody was incubated at 2 μg/mL on a glycan array containing 610 distinct glycans (glycan array version 5.1 from the Consortium for Functional Glycomics). The graph includes the glycans showing the highest levels of binding by any of the antibodies. For each antibody, we normalized the raw fluorescence values to set the highest value to 1. The list specifies the glycans included in the plot, and the labels above the columns indicate the primary motif in each glycan. DRG is the Assay 1 antibody, 9L426 is the Assay 2 antibody, and M081221 is another anti-sialyl Lewis A antibody included for comparison.
Mentions: Both antibodies bound the canonical CA 19–9 antigen—sialyl Lewis A—but with differences (Fig 3 and Fig 4). The antibody from Assay 2 (9L426) bound more strongly than the Assay 1 antibody to dimeric sLeA-LeA, as evidenced by the better signal at the low concentration of 0.2 μg/mL, but it showed no binding to the sialic acid variant Neu5Gc. It also bound to sialyl Lewis C (non-fucosylated sialyl Lewis A) at the relatively high concentration of 20 μg/mL. In contrast, the Assay 1 antibody (only the detection antibody was available from the commercial kit) showed greater binding to Neu5Gc but no additional binding to sLeC. A third antibody (clone M081221, Fitzgerald, Acton, MA), not used in Assay 1 or 2 but included for comparison, bound other glycans in addition to those displaying the canonical CA 19–9 antigen. This antibody cross-reacted with glycans containing sialyl Lewis X, an isomer of sialyl Lewis A in which the attachment of the fucose and galactose to the core structure is switched. Thus the CA 19–9 antibodies have overlapping but distinct specificities, including binding to some structures beyond the canonical CA 19–9 antigen.

Bottom Line: We gained additional information about the biomarker by comparing two distinct assays.The two CA 9-9 assays agreed well in overall performance but diverged in measurements of individual samples, potentially due to subtle differences in antibody specificity as revealed by glycan array analysis.Thus, the reference set promises be a valuable resource for biomarker validation and comparison, and the CA 19-9 data presented here will be useful for benchmarking and for exploring relationships to CA 19-9.

View Article: PubMed Central - PubMed

Affiliation: Van Andel Research Institute, Grand Rapids, MI, United States of America.

ABSTRACT
The validation of candidate biomarkers often is hampered by the lack of a reliable means of assessing and comparing performance. We present here a reference set of serum and plasma samples to facilitate the validation of biomarkers for resectable pancreatic cancer. The reference set includes a large cohort of stage I-II pancreatic cancer patients, recruited from 5 different institutions, and relevant control groups. We characterized the performance of the current best serological biomarker for pancreatic cancer, CA 19-9, using plasma samples from the reference set to provide a benchmark for future biomarker studies and to further our knowledge of CA 19-9 in early-stage pancreatic cancer and the control groups. CA 19-9 distinguished pancreatic cancers from the healthy and chronic pancreatitis groups with an average sensitivity and specificity of 70-74%, similar to previous studies using all stages of pancreatic cancer. Chronic pancreatitis patients did not show CA 19-9 elevations, but patients with benign biliary obstruction had elevations nearly as high as the cancer patients. We gained additional information about the biomarker by comparing two distinct assays. The two CA 9-9 assays agreed well in overall performance but diverged in measurements of individual samples, potentially due to subtle differences in antibody specificity as revealed by glycan array analysis. Thus, the reference set promises be a valuable resource for biomarker validation and comparison, and the CA 19-9 data presented here will be useful for benchmarking and for exploring relationships to CA 19-9.

No MeSH data available.


Related in: MedlinePlus