Carcinoembryonic Antigen, Ferritin, Tissue Polypeptide Antigen, and Ca15/3 in Breast Cancer: Relationship between Carcinoma and Normal Breast Tissue

The study of tumor markers in breast cancer tissue may supply information on the tumor's biological features and its clinical behaviour. Forty-nine primary breast cancer patients are evaluable to date. CEA, ferritin, TPA and CA15/3 were measured with radioimmu-nometric methods in the cytosol of carcinoma and normal tissue from the same breast. The concentrations of the four markers were higher in the tumor than in normal tissue in 42/49 cases for CEA, 47/49 for ferritin, 42/49 for TPA and in 24/29 for CA15/3. However, an overlap was found between carcinoma and normal tissue levels, particularly for CEA and TPA. We can conclude that the four substances studied may be markers of malignancy in breast carcinoma when nonmalignant breast tissue from the same patient is determined at the same time, whereas assays within a single, unknown breast tissue sample may be useful only in the case of ferritin and, partly, CA15/3.

Estrogen and Progesterone Receptors in Breast Carcinoma and in Nonmalignant Breast Tissue

Since 1983 we have studied the relationship, in the same patient, between receptor status in breast carcinoma and in nonmalignant breast tissue. Fifty patients have been evaluated to date. The total unoccupied cytosol estrogen and progesterone receptors were determined by a dextran-coated charcoal method. In nonmalignant breast tissue we found a measurable receptor concentration above the sensitivity of the method in 62 % of cases for estrogen receptors and in 44 % of cases for progesterone receptors. No relationships were found between the receptor level of each tumor and that of the corresponding benign tissue. The data suggest that the levels of the receptors in the tumor and in the nonmalignant tissue are totally independent.

Evaluation of HER-2/neu in Serum and Tissue of Primary and Metastatic Breast Cancer Patients using an Automated Enzyme Immunoassay

Serum HER-2/neu concentrations were evaluated in 172 healthy subjects, 176 primary and 55 metastatic breast cancer patients, employing a new automated assay (Bayer Immuno 1™ serum HER-2/neu). Using 13 ng/mL as the cutoff, abnormal HER-2/neu serum levels were found in 8% (14/176) of primary and 50.9% (28/55) of metastatic breast cancer patients.

Both in primary and metastatic breast cancer a significant relationship was found with the stage of the disease when serum HER-2/neu was considered as a categorized variable (p=0.0003 and p=0.02, respectively), but not when it was taken as a continuous variable (p=0.247 and p=0.146, respectively). Moreover, we evaluated the correlation between Immuno 1™ HER-2/neu and Oncogene Research Products ELISA assay in 53 normal subjects, 46 primary and 34 metastatic breast cancer patients. The correlation was relatively good (p<0.0001), although substantial differences could be found in single cases. The Immuno 1™ assay was also evaluated for the first time in breast cancer tissue. The method, which showed good performance both in terms of imprecision and linearity, was used to measure HER-2/neu protein in 140 cytosol samples from primary breast cancer tissue and in homogenates from 40 matched cases. The correlation between the two matrixes was very close (p<0.0001). By contrast, no correlation was found between serum and matched cytosol (p=0.101) or ho-mogenate samples (p=0.511).

Validation of Blood Collection Procedures for the Determination of Circulating Vascular Endothelial Growth Factor (VEGF) in Different Blood Compartments

Aims of the study.

Studies on circulating VEGF have reported mixed results, possibly due to a lack of standardization of the pre-analytical phase. The aim of our investigation was to standardize the sampling procedure for the determination of VEGF in different blood fractions.

Basic procedures.

We evaluated various clotting times for obtaining serum in 30 subjects, as well as different procedures for the preparation of plasma Edinburgh anticoagulant mixture (EDTA, PGE1, theophylline) and CTAD. VEGF was also assayed in lysed whole blood. In vitro platelet activation was monitored by measuring the levels of PF4. VEGF and PF4 were measured using commercially available enzyme-linked immunoassays.

Main findings.

Clotting time increased the release of VEGF, which reached a plateau between 2 and 4 hours. The percent increase of VEGF at 2 hours ranged from 118% to 4515% (median 327%) compared to samples centrifuged within 10 min from withdrawal. VEGF was not different and PF4 was very low or undetectable in Edinburgh plasma and CTAD plasma, while it was significantly higher in sodium citrate plasma. VEGF in CTAD plasma was not correlated with platelet count or leukocytes. Serum VEGF did not correlate with the leukocyte number, but it correlated significantly with the platelet count.

Principal conclusions.

The procedures for sample collection described above are highly standardized and easy to perform in a routine setting. We therefore suggest systematic evaluation of VEGF in CTAD plasma, in serum (clotting for 2 hours at room temperature) and in whole blood, until prospective controlled clinical studies will have clarified in which blood compartment(s) VEGF provides clinically relevant information.

How Tumor Markers are used in the Routine Follow-up of Breast and Colorectal Cancer. A Survey of 29 Italian Hospitals

The impact of tumor markers on the outcome of several malignancies is still under debate. This relative uncertainty leads to a subjective approach to their use. Monitoring the use of tumor markers is a valuable tool to identify the need for educational policies. We conducted a survey to evaluate how tumor markers are routinely used in the follow-up of patients with breast, colorectal and ovarian carcinoma. The former two malignancies are considered in the present paper. We surveyed 35 Italian hospitals; 29 (83%, accounting for 26,622 hospital beds) filled in and returned the questionnaire. Overall, 467,361 tumor marker requests were scrutinized by the surveyed hospitals. We found a wide variability in the type and number of routinely used markers, the cutoff points chosen, and the clinical decisions taken on the basis of marker results. In addition, we observed a relative lack of communication between clinicians and clinical pathologists in around 50% of the surveyed hospitals. In these cases clinical information was not provided to the laboratory and methodological aspects were not communicated to clinicians. From the findings of the present study we conclude that the cooperation between clinicians and clinical pathologists must improve before guidelines for the use of tumor marker assays can be framed and the compliance with these guidelines can be checked. Request forms for tumor marker assays should therefore be designed to contain clinical information and the quality of filling in request forms with clinical data should be carefully monitored.

Molecular Detection of Codon 12 K-RAS Mutations in Circulating DNA from Serum of Colorectal Cancer Patients

Point mutations of the K-RAS gene at codon 12 are found in about 40% of cases with colorectal cancer. The diagnostic implications of the detection of these mutations and their clinical utility are still unclear. The aim of this study was to test both the feasibility of the detection of the mutated K-RAS gene in serum and its potential role in colorectal cancer detection and monitoring.

Codon 12 K-RAS mutations were examined in DNA extracted from the serum of 35 patients with colorectal cancer and were compared with the K-RAS status in the corresponding primary tumor. Molecular detection was performed by the mutant-enriched PCR (ME-PCR) assay, a sensitive method capable of distinguishing a small quantity of mutated DNA in the presence of abundant wild-type DNA. The occurrence of mutations was compared with clinicopathological parameters as well as CEA and CA19.9 serum levels.

We found codon 12 K-RAS mutations in the tissue of 13/35 (37%) patients. Serum mutations were detected in 5/13 (38.5%) patients with mutated K-RAS in the tissue. 26/35 (74%) patients showed an identical K-RAS pattern in tissue and serum. No codon 12 K-RAS alterations were found in serum samples of 22 patients with benign gastrointestinal diseases. Elevated serum CEA levels were detected in 16 patients, four of whom also presented serum RAS mutations.

Our results confirm that K-RAS mutations can be found in circulating DNA extracted from serum samples of patients with colorectal cancer and show that there is a correspondence between serum and tissue K-RAS patterns.

Interchangeability and Diagnostic Accuracy of Two Assays for Total and Free Prostate-Specific Antigen: Two not Always Related Items

The variation between different PSA assays seems to influence the interpretation of individual PSA values and the clinical decisions about prostate cancer. One reason for this variability could be the different reactivity of antibodies for the various molecular forms of serum PSA; as a result, samples containing the same amount of tPSA but different proportions of fPSA can produce very different values. In this study, serum samples were collected prospectively from 152 consecutive patients referred to 2 institutions (Regional Hospital, Venice, 90 subjects; San Bortolo Hospital, Vicenza, 62 subjects) for PSA elevation and/or symptoms. Serum samples were assessed according to the manufacturers’ instructions on the following 2 analyzers: the Immulite 2000 assay (Diagnostic Products Corporation, Los Angeles, USA), which measures tPSA and fPSA, and the ADVIA Centaur (Bayer Diagnostics, Tarrytown, USA), which assays tPSA and cPSA. cPSA values were transformed into fPSA by the equation fPSA=tPSA-cPSA. When taking Immulite tPSA and f/tPSA values as 100%, ADVIA Centaur values were 92.6% and 122%, respectively, which means that 20% of patients would be classified differently according to the traditional biopsy cutoff. In conclusion, there are considerable differences between the 2 methods, which could affect clinical decisions.

A Prediction Model for Breast Cancer Recurrence after Adjuvant Hormone Therapy

Hormone therapy with tamoxifen has long been the established adjuvant treatment for node-positive, estrogen–receptor-positive breast cancer in postmenopausal women. Since 30–40% of these patients fail to respond, reliable outcome prediction is necessary for successful treatment allocation. Using pathobiological variables (available in most clinical records: tumor size, nodal involvement, estrogen and progesterone receptor content) from 596 patients recruited at a comprehensive cancer center, we developed a prediction model which we validated in an independent cohort of 175 patients recruited at a general hospital. Calculated at 3 and 4 years of follow-up, the discrimination indices were 0.716 [confidence limits (CL) 0.641, 0.752] and 0.714 (CL 0.650, 0.750) for the training data, and 0.726 (CL 0.591, 0.769) and 0.677 (CL 0.580, 0.745) for the testing data. Waiting for more effective approaches from genomic and proteomic studies, a model based on consolidated pathobiological variables routinely assessed at relatively low costs may be considered as the reference for assessing the gain of new markers over traditional ones, thus substantially improving the conventional use of prognostic criteria.

The Prognostic Value of Vascular Endothelial Growth Factor, Urokinase Plasminogen Activator and Plasminogen Activator Inhibitor-1 in Node-Negative Breast Cancer

The vascular endothelial growth factor (VEGF) and the plasminogen activator system play an essential role in solid tumor angiogenesis and in tumor invasion and metastasis. In the present study we investigated the relationship between patient outcome and levels of VEGF, urokinase plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in tumor cytosols of 196 node-negative primary invasive breast cancer patients who did not receive any adjuvant therapy. The median follow-up was 65 months. VEGF, uPA and PAI-1 were measured by commercially available enzyme-linked immunosorbent assays. Cox's univariate analysis showed that pT (p=0.0007), uPA (p=0.0156) and PAI-1 (p=0.0015) had a significant impact on relapse-free survival, whereas VEGF did not have any prognostic value (p=0.18). Bivariate analysis showed significant interactions between uPA and PAI-1 (p=0.0035) and between VEGF and PAI-1 (p=0.006). Our study confirms that uPA and PAI-1 cytosol levels can be considered as prognostic factors for relapse-free survival in node-negative breast cancer. Moreover, the interaction between VEGF and PAI-1 warrants further investigation into the relationship between the biomarkers of angiogenesis and those of the protease cascade.

Comparison between Two Methods in the Determination of Circulating Chromogranin A in Neuroendocrine Tumors (NETs): Results of a Prospective Multicenter Observational Study

Several methods for analyzing CgA using either monoclonal or polyclonal antibodies have been developed, which differ in their diagnostic performance. The present paper describes the results of a prospective multicenter study aimed at comparing the clinical value of the two most widely used commercially available CgA assay kits in patients affected by neuroendocrine tumors (NETs). Two hundred sixty-one patients from 40 different centers and 99 healthy subjects were evaluated. CgA levels were measured with two different methods, a two-step immunoradiometric assay (IRMA) and an enzyme-linked immunosorbent assay (ELISA). CgA was measured centrally by two reference laboratories, one of which used IRMA and the other ELISA, and it was measured by the participating institutions with the method routinely used by each of them. The major findings of the present study were: (i) the two assays for the determination of CgA present good diagnostic performance; (ii) both assays are robust and guarantee comparable results when applied in different settings (central vs local laboratory); (iii) the negative/positive cutoff points (87 ng/mL for IRMA and 21.3 U/L for ELISA) were established according to standardized criteria; (iv) the results obtained with the two assays in basal clinical samples of patients affected by NETs show an apparently satisfactory correlation (rs=0.843, p<0.0001). However, a possibly clinically meaningful 36% discordance rate was found. These findings support the hypothesis that the two CgA kits might provide partially different information.

Reassessment of the Access Testosterone chemiluminescence assay and comparison with LC-MS method

AIM OF THE STUDY

To reassess the imprecision and Limit of Quantitation, to evaluate the cross-reaction with dehydroepiandrosterone-sulfate (DHEAS), the accuracy toward liquid chromatography-mass spectrometry (LC-MS) and the reference interval of the Access Testosterone method, performed by DxI immunoassay platform (Beckman Coulter).

MATERIAL AND METHODS

Imprecision was evaluated testing six pool samples assayed in 20 different run using two reagents lots. The cross-reaction with DHEAS was studied both by a displacement curve and by spiking DHEAS standard in two serum samples with known amount of testosterone. The comparison with LC-MS was evaluated by Passing-Bablock analysis in 21 routine serum samples and 19 control samples from an External Quality Assurance (EQA) scheme. The reference interval was verified by an indirect estimation on 2445 male and 2838 female outpatients.

RESULTS

The imprecision study showed a coefficient of variation (CV) between 2.7% and 34.7% for serum pools from 16.3 and 0.27 nmol/L. The value of Limit of Quantitation at 20% CV was 0.53 nmol/L. The DHEAS showed a cross-reaction of 0.0074%. A comparison with LC-MS showed a trend toward a slight underestimation of immunoassay vs LC-MS (Passing-Bablock equations: DxI=-0.24+0.906 LCMS in serum samples and DxI=-0.299+0.981 LCMS in EQA samples). The verification of reference interval showed a 2.5th-97.5th percentile distribution of 6.6-24.3 nmol/L for male over 14 years and <0.5-2.78 nmol/L for female subjects, in accord with the reference intervals reported by the manufacturer.

CONCLUSIONS

The Access Testosterone method could be considered an adequately reliable tool for the testosterone measurement.

Harmonization protocols for TSH immunoassays: a multicenter study in Italy

Background:

Systematic difference between thyroid-stimulating hormone (TSH) immunoassays may produce misleading interpretation when samples of the same patients are measured with different methods. The study aims were to evaluate whether systematic differences are present among TSH immunoassays, and whether it is possible to obtain a better harmonization among TSH methods using results obtained in external quality assessment (EQA) schemes.

Methods:

Seven Italian clinical laboratories measured TSH in 745 serum samples of healthy subjects and patients with thyroid disorders. These samples were also re-measured by two reference laboratories of the study with the six TSH immunoassays most popular in Italy after 2 months of storage at −80 °C. Moreover, these data were compared to 53,823 TSH measurements, obtained by laboratories participant to 2012–2015 EQA annual cycles in 72 quality control samples (TSH concentrations from about 0.1 mIU/L to 18.0 mIU/L). TSH concentrations were recalibrated using a mathematical approach based on the principal component analysis (PCA).

Results:

Systematic differences were found between the most popular commercially available TSH immunoassays. TSH concentrations measured by the clinical laboratories were very closely correlated to those measured with the same method by reference laboratories after 2 months of storage at −80 °C. After recalibration using the PCA approach the variation of TSH values significantly decreased from a median pre-calibration value of 13.53% (10.79%–16.53%) to 9.63% (6.90%–13.21%) after recalibration.

Conclusions:

Our data suggest that EQA schemes are useful to improve harmonization among TSH immunoassays and also to produce some mathematical formulas, which can be used by clinicians to better compare TSH values measured with different methods.

Tumour markers requesting pattern with regards to different organizational settings in Italy: a survey of hospital laboratories

Background

Tumour markers are frequently used in clinical practice and the reason for ordering varies considerably and often seems to be inappropriate. We carried out a survey of Italian laboratories on their current pattern of use.

Methods

Forty-four laboratories located in health-care institutions with inpatient beds were surveyed about the organizational, clinical and methodological aspects of tumour markers ordering.

Results

Thirty-one laboratories (70%) filled in and returned the questionnaire. Overall, 977,786 tumour marker tests were scrutinized. The pattern of tumour marker use did not seem to be influenced by the institutional setting, by availability of oncology facilities or by adoption of clinical guidelines. In addition, the information flow from clinicians to the laboratory and vice versa was poor and informal.

Conclusions

Monitoring tumour marker pattern use can provide valuable information for health-care decision makers, highlighting potential inadequacies in laboratory services but also identifying problems in other areas of health-care delivery that could benefit from educational programmes.

An Italian program of External Quality Control for chromogranin A (CgA) assay: performance evaluation of CgA determination

BACKGROUND

Chromogranin A (CgA) is an acidic glycoprotein produced by many neuroendocrine cells and neurons. Currently, two different methods for assaying CgA, immunoradiometric assay (IRMA) and enzyme-linked immunosorbent assay (ELISA), are widely used in routine practice. Within the framework of a Ministry of Health project, an External Quality Control program was developed to investigate the state of the art of CgA determination in Italy and to monitor the performance of laboratories carrying out this assay. This paper reports the results regarding laboratory performance.

METHODS

A total of 43 laboratories participated in this program, in which 21 used the ELISA method and 22 the IRMA method. Each laboratory received six samples, three aliquots of serum and three of plasma, at high, intermediate and low concentrations. The results provided by the two assay methods were analyzed separately using two statistical approaches, the principal component analysis and the control chart method.

RESULTS

For the IRMA method, questionable results for all samples were obtained by two laboratories, while in two other laboratories performance was questionable for only one sample. For the ELISA method, questionable performances were obtained in only one laboratory for the low and intermediate concentration samples, whereas in three laboratories performance was questionable for only one sample. Interestingly, the coefficients of variation increased approximately five-fold when shifting from the IRMA to the ELISA method.

CONCLUSIONS

This program demonstrated both the requirement and demand for external quality assessment of CgA assay.