• Component Description
• Eligible Sample
• Description of Laboratory Methodology
• Laboratory Quality Assurance and Monitoring
• Data Processing and Editing
• Analytic Notes
• References
• Codebook
  • SEQN - Respondent sequence number
  • SSCA125L - Cancer antigen 125 IgG luminescent units
  • SSCA125I - Cancer antigen 125 IgG index
  • SSCA153L - Cancer antigen15.3 IgG luminescent unit
  • SSCA153I - Cancer antigen 15.3 IgG index
  • SSHE4L - HE4 IgG luminescent units
  • SSHE4I - HE4 IgG index

National Health and Nutrition Examination Survey

2001-2002 Data Documentation, Codebook, and Frequencies

Cancer antigen CA125, CA15.3 and HE4 IgG antibodies - Serum (Surplus) (SSCGA_B)

Data File: SSCGA_B.xpt

First Published: August 2022

Last Revised: NA

Component Description

Sera from residual specimens from NHANES 2001-2002 participants were tested for levels of IgG antibodies against cancer antigen (CA) 125, CA15.3 and human epididymal secretory protein 4 (HE4). The results are reported as relative luminescence units and as an index of relative specific autoimmune reactivity compared to non-specific/heterophilic IgG binding to albumin.

Eligible Sample

Female participants age 20+ who consented to storing their samples for future research and had stored samples from 2001-2002.

Description of Laboratory Methodology

All measurements were performed in the Genital Tract Biology Laboratory (Brigham and Women’s Hospital, Lab Director Fichorova) following pre-analytic, analytic, and post-analytic standardized operational procedures (SOPs) established under the Laboratory Director and special chemistry accreditation by the College of American Pathologists. The lab used the Meso Scale Discovery (MSD) (Gaithersburg, MD) electrochemiluminescence immunoassay platform. Quality control (QC) pools were prepared and split into multiple aliquots. To establish inter-and intra-plate variability, one aliquot of this pool was repeatedly tested on each assay plate. A coefficient of variation of < 25% was set as a threshold for acceptance of the data.

In further detail, the following assays and methodology were applied:

Human Custom Antibody Assay 7-spot, 3-plex, MSD, cat # N75YA-1

Assay design: For this custom assay design, the Laboratory of Genital Tract Biology provided to Meso Scale Discovery the following proteins to be coated each on one spot of the 7-spot test plates: Human antigen grade CA125 purified from an ovarian cancer cell line (Meridian Life Sciences Inc, Memphis, TN, cat # A97180H), human antigen grade CA15.3 derived from human breast cancer BTA cell line supernatant (Meridian, cat # A32000H), and recombinant full-length human HE4 expressed in HEK 293 cells (Abcam, Cambridge, MA, cat #ab152016).

The CA125 antigen preparation showed analytically negligible contamination with other mucins (<0.23% for CA19-9 and <0.01% for CA15-3, by Elecsys).  The CA15.3 antigen preparation also minimal contamination with CA15.3 (0.2%, Cobas CA19-9 Assay) and CA125 (2.49%, Cobas CA125 Assay). The purity of the recombinant HE4 antigen was > 95%, determined by SEC-HPLC and reducing SDS-PAGE (full length sequence of the recombinant protein: EKTGVCPELQADQNCTQECVSDSECADNLKCCSAGCATFCSLPNDKEGSCPQVNINFPQL GLCRDQCQVDSQCPGQMKCCRNGCGKVSCVTPNFVDHHHHHH). The remaining four spots of the 7-spot plate were coated by MSD with bovine serum albumin.

The assays included blocking with a blocking buffer for 1h and with sample diluent for 30 minutes, followed by PBS/0.05% Tween-20 wash; 2h incubation with samples at multiple dilutions followed by wash; detection of human IgG bound to the specific protein spots with an MSD sulfo-Tag-labeled mouse monoclonal detection antibody (10 μg/ml) for 2h; washing and adding read buffer followed by detection of electro-chemiluminescence (ECL) using an MSD Imager S600.  All NHANES serum biospecimens were tested at a 10-fold dilution and repeated at a 50-dold dilution if producing an outlier value in the specific antigen or albumin spots.

Laboratory Quality Assurance and Monitoring

A quality control (QC) pooled sample was generated from pooling equal volumes of serum samples from ovarian cancer cases and split aliquots of the QC pool were tested at three different dilutions (2, 10, 50 and 250-fold) in triplicate on each assay plate to determine intra- and inter-assay variation. The Coefficient of variation (CV) was calculated as 100*standard deviation of replicate values / average or replicate values. The acceptable QC pool variation was set to 25%. Back fit analysis of each calibrator was also set to 25% acceptable level. Outliers were confirmed by repeated testing. The following intra- and inter-assay CV of the three dilutions (2x, 10x and 50x) tested were recorded for the specific IgG reactivity:  1) Intra-assay CVs were:  CA15.3 - 3.7 % (2x), 9.4 % (10x), 15.5% (50x) and 17.9 % (250x); CA125 - 8.9 % (2x), 9.4 % (10x), 11.8 % (50x) and 15.5 % (250x); HE4 - 15.5 % (2x), 10.2 % (10x), 8.4 % (50x) and 8.2% (250x); 2) Inter-assay CVs were: CA15.3 - 9.9 % (2x) 15.5 % (10x) and 22.4 % (50x) and 87.2% (250x); CA125 – 20 % (2x), 17 % (10x), 23 % (50x) and 30.3% (250x); HE4 – 28 % (2x), 24 % (10x) and 22 % (50x), and 22.4% (250x). The QC data showed that while IgG binding to some of the antigens (CA5.3) was below precision range at the 250x dilution, both the 10x and 50x dilutions chosen for the screening of all NHANES samples generated reliably reproducible signal of IgG binding to all three mucin antigens.

Data Processing and Editing

Data was compiled into a database after all the assays were completed and passed quality control criteria. The data were not edited.

Data Access: All data will be made publicly available.

Analytic Notes

The results are reported as relative luminescence units (RLU) and as an index of relative specific autoimmune reactivity compared to non-specific/heterophilic IgG binding to albumin calculated as average RLU of specific antigen spot divided by average RLU of signal from 4 BSA-coated spots.

Exam sample weights should be used for analyses. Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial for further details on the use of sample weights and other analytic issues.

References

• Cramer DW, Fichorova RN, Terry KL, Yamamoto H, Vitonis AF, Ardanaz E, et al. Anti-CA15.3 and Anti-CA125 Antibodies and Ovarian Cancer Risk: Results from the EPIC Cohort. Cancer Epidemiol Biomarkers Prev. 2018;27(7):790-804.
• Fortner RT, Schock H, Le Cornet C, Husing A, Vitonis AF, Johnson TS, et al. Ovarian cancer early detection by circulating CA125 in the context of anti-CA125 autoantibody levels: Results from the EPIC cohort. Int J Cancer. 2018;142(7):1355-60.

Codebook and Frequencies