Alternative antibody for the detection of CA19-9 antigen: a European multicenter study for the evaluation of the analytical and clinical performance of the Access GI Monitor assay on the UniCel Dxl 800 Immunoassay System

Establishment of CA19-9 reference intervals in an apparently healthy adult population in Singapore

BACKGROUND

CA19-9 is elevated in pancreatic cancer and other malignancies, and commonly used in clinical practice. Unfortunately, CA19-9 immunoassays are not harmonized, and reference intervals may differ between assays. The aim of this study was to establish the reference interval of the ADVIA Centaur/Atellica IM CA19-9 assay in an apparently healthy Singapore adult population.

METHODS

This is a retrospective cross-sectional study. De-identified data from Health Screening participants were extracted from our database. Subjects with biochemical results suggesting anaemia, diabetes mellitus, viral hepatitis or abnormal liver, and renal and tumour markers were excluded. Outlier and subclass analyses by age and sex were performed. CA19-9 reference limits and 90% confidence intervals were then determined for candidate subclasses.

RESULTS

Data from 12,174 subjects (5846 males and 6328 females) were available after exclusion criteria were applied. CA19-9 results did not follow a normal distribution and were higher in females compared to males (P < .001). Although CA19-9 means were statistically different between certain age groups, the evaluable 99th percentile reference limits were not statistically different. The overall 99th percentile reference limits for the Centaur/Atellica CA19-9 assay was 37 U/mL for males 21-80 years, and 60 U/mL for females 21-80 years.

CONCLUSIONS

Our results suggest that separate CA19-9 reference intervals should be applied for males and females.

Longitudinal evaluation of external quality assessment results for CA 15-3, CA 19-9, and CA 125

Background

Tumor markers are established laboratory tools that help to diagnose, estimate prognosis, and monitor the course of cancer. For meaningful decision-making in patient care, it is essential that methods and analytical platforms demonstrate high sensitivity, specificity, precision, and comparability. Regular participation at external quality assessment (EQA) schemes is mandatory for laboratories. Here, a longitudinal evaluation of EQA data was performed to assess the performance of tumor marker assays over time.

Methods

Longitudinal data of the cancer antigens (CA) 15-3 (n = 5,492), CA 19-9 (n = 6,802), and CA 125 (n = 5,362) from 14 INSTAND EQAs conducted between 2019 and 2023 were evaluated. A median of 197, 244 and 191 laboratories participated at the EQAs for CA 15-3, CA 19-9 and CA 125, respectively. Data evaluation encompasses intra- and inter-manufacturer specific variations over time, assay precision, and adherence to the EQA limits of ±24% for CA 15-3, ±27% for CA 19-9 and ±36% for CA 125.

Results

The study showed median manufacturer-dependent differences of up to 107% for CA 15-3, 99% for CA 125, and even 549% for CA 19-9 between the highest and the lowest methods over the studied period. Regarding the normalized median of all methods, the values of the most deviant methods were 0.42 for CA 15-3, 7.61 for CA 19-9, and 1.82 for CA 125. Intra-manufacturer variability was generally low, with median coefficients of variation (CV) below 10%. As the methods were evaluated according to method-specific consensus values, most participants passed the EQAs within the acceptance criteria. When the criteria were consistently set at 24%, the central 90% of participants passed the EQAs in 78.6%-100% for CA 15-3 (with exception of AX), 89.3%-100% for CA 125, and 64.3%-100% for CA 19-9.

Conclusion

While intra-method precision of most analytical platforms is acceptable for all three tumor markers, considerable inter-method variability was observed over the whole studied period demonstrating the necessity for better standardization and harmonization of the methods, development of international reference materials, and comprehensive commutability studies with patient samples.

Factors influencing blood tumor marker concentrations in the absence of neoplasia

BACKGROUND

Tumor markers (TMs) are a heterogeneous group of molecules used in the diagnosis, prognosis and follow-up of cancer patients. During neoplastic differentiation, cells can either directly synthesize or induce the synthesis of TMs, and the release of these molecules into the bloodstream allows their quantification in biological fluids. Although very small concentrations of TMs are usually present in the serum or plasma of healthy subjects, increased concentrations may also be found in the presence of benign diseases or due to technical interference, producing false positive results.

MATERIAL AND METHODS AND RESULTS

Our review analyses the causes of false positives described between January 1970 to February 2023 for the TMs most frequently used in clinical practice: α-fetoprotein (AFP), β2-microglobulin (β2-M), cancer antigen 15-3 (CA 15-3), cancer antigen CA 19-9 (CA 19-9), cancer antigen CA 72-4 (CA 72-4), cancer antigen 125 (CA 125), carcinoembryonic antigen (CEA), chromogranin A (CgA), choriogonadotropin (hCG), cytokeratin 19 fragment (CYFRA 21-1), neuron-specific enolase (NSE), human epididymis protein 4 (HE4), serum HER2 (sHER2), squamous cell carcinoma antigen (SCCA), protein induced by vitamin K absence-II (PIVKA-II), Pro-gastrin-releasing peptide (Pro-GRP), prostate-specific antigen (PSA), Protein S-100 (S-100) and thyroglobulin (Tg). A total of 247 references were included.

CONCLUSIONS

A better understanding of pathophysiological processes and other conditions that affect the concentration of TMs might improve the interpretation of results and their clinical application.

Method Comparison and Clinical Performance of Breast Cancer Tumor Markers on Novel Multiplex Immunoassay and Automatized LOCI Technology Platforms

Tumor marker determinations are valuable tools for the guidance of breast cancer patients during the course of disease. They are assessed on diverse analytical platforms that may be associated with differences according to the methods applied and the clinical performance. To investigate the method dependency and clinical significance of breast cancer protein tumor markers, CEA, CA 15-3, CA 125, CA 19-9 and AFP were measured in a total of 154 biobanked samples from 77 patients with breast cancer, 10 with DCIS, 31 with benign breast diseases and 36 healthy controls using a Millipore multiplex biomarker panel (MP) and an automized version of the routinely used Vista LOCI technology. The markers were compared between methods and investigated for diagnostic performance. CEA, CA 15-3 and AFP showed good correlations between both platforms with correlation coefficients of R = 0.85, 0.85 and 0.92, respectively, in all samples, but similarly also in the various subgroups. CA 125 and CA 19-9 showed only moderate correlations (R = 0.71 and 0.56, respectively). Absolute values were significantly higher for CEA, CA 15-3, CA 125 and AFP in the Vista LOCI as compared with the MP method and vice versa for CA 19-9. The diagnostic performance for discrimination of breast cancer from healthy controls was similar for both methods with AUCs in ROC curves for CEA (MP 0.81, 95% CI 0.72-0.91; LOCI 0.81; 95% CI 0.72-0.91) and CA-15-3 (MP 0.75, 95% CI 0.65-0.86; LOCI 0.67, 95% CI 0.54-0.79). Similar results were obtained for the comparison of breast cancer with benign breast diseases regarding CEA (AUC MP 0.62, 95% CI 0.51-0.73; LOCI 0.64, 95% CI 0.53-0.74) and CA-15-3 (MP 0.70, 95% CI 0.6-0.81; LOCI 0.66, 95% CI 0.54-0.77). Both platforms show moderate to good method comparability for tumor markers with similar clinical performance. However, absolute levels in individual patients should be interpreted with care.

Improved sensitivity for detection of breast cancer by combination of miR-34a and tumor markers CA 15-3 or CEA

Background

MicroRNAs biomarkers have shown value for diagnosis and prognosis of various cancers. Combination with established tumor markers has rarely been done.

Results

Breast cancer patients had significantly higher serum RNA loads (AUC 0.665), lower miR-34a (AUC 0.772), higher CEA and CA 15-3 levels (AUCs 0.717 and 0.721) than healthy controls. miR-34a correlated with tumor stage and hormone receptor status. There was no significant difference between groups for all other miRNAs. Combination of miR-34a with CEA or CA 15-3 led to improved AUCs of 0.844 and 0.800, respectively. Sensitivity of miR-34a and CA 15-3 reached 56.1% at 95% specificity. When compared with benign breast diseases, combination of miR-34a (AUC 0.719) and CEA (0.623) or CA 15-3 (0.619) resulted in improved performances (0.794 and 0.741). Sensitivity of miR-34a and CA 15-3 reached 53.7% at 95% specificity.

Conclusion

While miR-34a provides valuable information for diagnosis and staging, combination with tumor markers CA15-3 or CEA improves the sensitivity for breast cancer detection.

Patients and Methods

The diagnostic relevance of the miR-21, miR-34a, miR-92a, miR-155, miR-222 and miR-let-7c was tested in sera of 103 individuals (55 breast cancer, 20 benign breast diseases, 28 healthy controls). MiRNAs were detected by quantitative rt-PCR after extraction and reverse transcription. Cel-miR-39 and miR-16 were used for normalization. Established tumor markers CEA, CA 15-3, CA 19-9 and CA 125 were measured by automatized immunoassays. Diagnostic performance was tested by areas under the curve (AUC) of receiver operating characteristic (ROC) curves and sensitivities at 90% and 95% specificity.

Evaluation of Beckman Coulter DxI 800 immunoassay system using clinically oriented performance goals

OBJECTIVES

We evaluated the analytical performance of 24 immunoassays using the Beckman Coulter DxI 800 immunoassay systems at Mayo Clinic, Rochester, MN for trueness, precision, detection limits, linearity, and consistency (across instruments and reagent lots).

METHODS

Clinically oriented performance goals were defined using the following methods: trueness-published desirable accuracy limits, precision-published desirable biologic variation; detection limits - 0.1 percentile of patient test values, linearity - 50% of total error, and consistency-percentage test values crossing key decision points. Local data were collected for precision, linearity, and consistency. Data were provided by Beckman Coulter, Inc. for trueness and detection limits.

RESULTS

All evaluated assays except total thyroxine were within the proposed goals for trueness. Most of the assays met the proposed goals for precision (86% of intra-assay results and 75% of inter-assay results). Five assays had more than 15% of the test results below the minimum detection limits. Carcinoembryonic antigen, total thyroxine and free triiodothyronine exceeded the proposed goals of ±6.3%, ±5% and ±5.7% for dilution linearity. All evaluated assays were within the proposed goals for instrument consistency. Lot-to-lot consistency results for cortisol, ferritin and total thyroxine exceeded the proposed goals of 3.3%, 11.4% and 7% at one medical decision level, while vitamin B12 exceeded the proposed goals of 5.2% and 3.8% at two decision levels.

CONCLUSIONS

The Beckman Coulter DxI 800 immunoassay system meets most of these proposed goals, even though these clinically focused performance goals represent relatively stringent limits.

CA 19-9 in pancreatic cancer: retrospective evaluation of patients with suspicion of pancreatic cancer

CA 19.9 serum levels were prospectively determined in 573 patients admitted to hospital for suspicion of pancreatic cancer. The final diagnosis was 77 patients with no malignancy, 389 patients with pancreatic cancer, 37 neuroendocrine pancreatic cancer, 28 cholangiocarcinomas, 4 gallbladder cancer, 27 ampullary carcinomas, and 11 periampullary carcinomas. CA 19.9 was determined using a commercial assay from Roche Diagnostics, and 37 U/ml was considered as the upper limit of normality. Abnormal CA 19.9 serum levels were found in 27%, 81.5%, 85.7%, 59.3%, 63.6%, and 18.9% of patients with benign diseases, pancreatic cancer, cholangiocarcinomas, and ampullary, periampullary, or neuroendocrine tumors. Significantly higher concentrations of CA 19.9 were found in patients with than in those without malignancy or with neuroendocrine tumors. CA 19.9 serum levels were higher in pancreatic cancer or cholangiocarcinoma than in other malignancies (p < 0.0001). CA 19.9 serum levels were also correlated with tumor stage, treatment (significantly lower concentrations in resectable tumors), and tumor location (the highest in those located in the body, the lowest in those in the tail or uncinate) and site of metastases (highest in liver metastases). A trend to higher CA 19.9 serum concentrations was found in patients with jaundice, but only with statistical significance in the early stages. Using 50 or 100 U/ml in patients with jaundice, CA 19.9 was useful as an aid in the diagnosis of pancreatic cancer (sensitivity 77.9%, specificity 95.9%) as well as tumor resectability in pancreatic cancer with different cutoffs according to tumor location and bilirubin serum levels with specificities ranging from 90% to 100%. CA 19.9 is the tumor marker of choice in pancreatic adenocarcinomas, with a clear relationship with tumor location, stage, and resectability.

Increased plasma concentrations of tumour markers in the absence of neoplasia

Tumour markers are a very heterogeneous group of molecules that are generally found in very small concentrations in the plasma and serum of healthy individuals. In the process of neoplastic differentiation the cell can synthesize, release, or induce synthesis of other cells, thus increasing their concentration in plasma and serum. These substances may also increase their plasma concentration in patients without cancer due to processes that increase the release or reduce catabolism, and so give rise to false positives. An understanding of the main physiopathological processes that increase the concentrations of these substances could improve our interpretation of tumour markers and their clinical application. In this study we review the physiopathological processes that may increase the plasma concentrations of tumour markers. We performed a bibliography review in PubMed, searching for causes of false positives for the following tumour markers: α-Fetoprotein, CA 125, CA 15-3, CA 19-9, CA 72-4, carcinoembryonic antigen, CYFRA 21-1, squamous cell carcinoma, prostatic specific antigen, β(2)-microglobulin, choriogonadotropin (β chain), chromogranin A, neuron specific enolase, HER2-neu, progastrin releasing peptide, S-100, and thyroglobulin. The results favour the use of tests which can identify pathological processes that may increase tumour marker concentrations.

Application of a time-varying covariate model to the analysis of CA 19-9 as serum biomarker in patients with advanced pancreatic cancer

PURPOSE

The clinical relevance of CA 19-9 as surrogate biomarker in advanced pancreatic cancer is a matter of debate.

EXPERIMENTAL DESIGN

This retrospective multicenter study included patients with histologically confirmed advanced pancreatic cancer treated with first-line therapy. Analysis of CA 19-9 was done using the Elecsys assay (Roche Diagnostics). For an analysis of CA 19-9 kinetics, at least three measurements during first-line chemotherapy had to be available. The effect of pretreatment CA 19-9 levels on time-to-progression (TTP) and overall survival (OS) was modeled by Cox proportional hazards regression. The effect of CA 19-9 kinetics was also modeled by Cox proportional hazards regression where CA 19-9 was treated as a time-varying covariate.

RESULTS

One hundred and fifteen patients from five German centers were included; 73% of them were treated within prospective clinical trials. Median TTP was 4.4 months and median OS was 9.4 months; univariate analysis indicated that pretreatment CA 19-9 [as continuous variable, log (CA 19-9)] was significantly associated with TTP [hazard ratio (HR), 1.24; P < 0.001] and OS (HR, 1.16; P = 0.002). These associations remained significant within multivariate analysis. For CA 19-9 kinetics during chemotherapy, data from 69 patients (TTP) and 84 patients (OS) were available, respectively; log (CA 19-9) kinetics after start of treatment were found to be a significant predictor for TTP in univariate (HR, 1.48; P < 0.001) and multivariate (HR, 1.45; P < 0.001) analyses, and also for OS (univariate: HR, 1.34; P < 0.001; multivariate: HR, 1.38; P < 0.001).

CONCLUSION

Pretreatment CA 19-9 and CA 19-9 kinetics may serve as a useful serum biomarker in advanced pancreatic cancer.