Pelizzola D

Characterization of laboratory working standard for quality control of immunometric and radiometric estrogen receptor assays. Clinical evaluation on breast cancer biopsies. Italian Committee for Hormone Receptor Assays Standardization.

The objective of the study was to characterize a low-cost and reliable working standard material for quality control of estrogen receptor (ER) determination with dextran-coated charcoal (DCC) and enzyme immunoassay (EIA) methods. Human fibromatous uterine lyophilized cytosol demonstrated good characteristics of stability and applicability for this purpose. Eleven laboratories participated in the intralaboratory and interlaboratory quality control study, and they achieved slightly higher coefficients of variation for ER-EIA (interlaboratory, 37.7 %; intralaboratory, 22.9 %) than for ER-DCC (Interlaboratory, 24.2 %; intralaboratory, 15.7 %). There was an excellent correlation between ER results with ER-EIA and ER-DCC for 268 breast cancer biopsies. Quality assurance for ER assays using DCC techniques and immunometric methods with monoclonal antibodies (ER-EIA) can be set up with this available material of human origin to satisfy the characteristics of both techniques and the species specificity of monoclonal antibodies.

Testis cytological structure, plasma sex steroids, and gonad cytosol free steroid receptors of heterologous gonadotropin (hCG)-stimulated silver eel, Anguilla anguilla L

Complete testicular maturation was induced in silver eels, kept at 24 degrees in fresh water, by a single injection of 1000 I.U. of heterologous gonadotropin (hCG). Each week, for 4 weeks, some eels were examined for testis structural pattern, plasma sex steroids, and gonad cytosol steroid receptors. The first effect of the hCG was on the tubular organization of the testis, followed by spermatogenesis. Plasma androgens were not detectable in the untreated eels, whereas a peak was detected a week after in those treated with the injection and afterward a decline. Plasma progesterone and estradiol showed a peak 2 weeks after treatment. Untreated eel gonads showed a high content of cytosolic free estradiol receptors which disappeared in the hCG-treated ones, a peak of free progesterone receptors was found 1 week after injection. The results are discussed in relation to the differentiation and maturation of eels testes.

Results of the Italian interlaboratory quality control program for estradiol receptor assay.

This article presents results of the first Italian quality control program for determining the estradiol receptor on lypophilized guinea pig and calf uteri. Despite considerable variability in quantitative terms, the results concur in ability to define samples as positive or negative for receptor content. One of the parameters that most strongly influences accuracy of determination of receptor concentration is protein assay. The evaluation of several lyophilized preparations at scalar concentrations permitted identification, by linear regression, for each laboratory of the systematic and non-systematic variables. More comparable results will be forthcoming when a standardized methodology program has been fully adopted.

Quality assurance for steroid receptor assay in human breast cancer: six years experience of the Italian Committee.

Since 1979 the quality control design proposed by the Italian ad hoc Committee has evaluated several lyophilized preparations with scalar receptor content; this permits the identification by linear regression analysis of systematic and non systematic errors. At present 41 laboratories from most of the national regions have joined the Italian Committee. The overall results of five years application of quality assurance in Italy show that there was a different pattern of imprecision with satisfactory indexes for intralaboratory performances but major variations in interlaboratory controls. There was also a remarkable difference of variability indices between the so-called « expert » and « new » laboratories; this problem can be reduced with practical seminars for new centers. On the basis of the results and experience achieved the Committee is starting another program of quality assurance for different new methodologies to provide guidelines for international working reference standards.

Comparison between single saturating dose ligand binding assay and enzyme immunoassay for low-salt extractable oestrogen and progesterone receptors in breast cancer: A multicentre study

An excellent correlation between ligand binding assay (LBA) and enzyme immunoassay (EIA) for both oestrogen (ER) and progesterone (PR) receptors has been reported. Nevertheless, considering that the clinical value of any discrepancy between LBA and EIA probably varies with the receptor level, we undertook a collaborative study in which a single saturating dose (SSD) LBA and EIA were compared in different ER and PR dose ranges. The values of ER measured by EIA were higher in tumours with low or intermediate receptor content, causing a misclassification of ER status in 9% of cases (ER+: 77.5%, EIA, 68.8% SSD). In the case of ER, EIA values tended to be higher than SSD in all centres. For PR, EIA and SSD were generally more comparable (PR+: 66.0% EIA, 72.0% SSD, discordance rate 6%), with EIA showing, however, different trends in different centres. PR concentration was not significantly different in ER SSD-/EIA+ and in ER SSD+/EIA+ cases, suggesting that EIA detects at least in part integer ER. We conclude that although EIA may be a reliable methodological alternative to SSD, the two methods are not interchangeable until effective cut-off levels for clinical decisions are assessed for EIA.

Hormone receptors and breast cancer: Correlations with clinical and histologic features

The possible relationships between hormone receptor status and several clinical (age, gynecologic history, clinical stage) and morphologic aspects (histologic grade, vascular invasion, lymphocytic infiltration, necrosis, fibrosis, elastosis and lymph node metastasis) were evaluated. A highly significant correlation between estrogen receptor levels, patient age, menses regularity and postmenopausal status was found. The histologic features most significantly related to tumor receptor status were histologic grade, lymphocytic infiltrate, necrosis and elastosis. Since these same histologic aspects appear to influence prognosis in breast cancer, the prognostic significance attributed to tumor receptor levels is substantiated. Therefore the importance of this assay is confirmed, not only for its diagnostic and therapeutic purposes, but also for its prognostic value.

Cathepsin D versus other prognostic factors in breast cancer. Results and controversies of a multicenter study on 2575 cases.

The aim of this study was the survey of cathepsin D determination in a large group of patients enrolled at several centers, under the coordination of the Italian Committee for Quality Control in the Oncological Laboratory. Cathepsin D was measured with the same method-ology, under control of an intra and interlaboratory quality control program, in order to verify the comparability of cathepsin D results from different institutions and to analyze the frequency of cathepsin D positive cases in subgroups of patients stratified according to other prognostic parameters. This retrospective study included 2575 patients with primary breast cancer evaluat-ed in 10 institutions. Cytosol from tumor tissue was the substrate for biochemical cathepsin D, estrogen receptor and progesterone receptor determination, with an interlaboratory quality control survey provided by the E.O.R.T.C. Receptor Group and the Italian Committee for Quality Control in the Oncological Laboratory. The results of the present study can be summarized as follows: 1) Cathepsin D is independent of menopausal status; 2) In spite of standardization of tissue handling and assay methods, different results may be obtained by different institutions. It is therefore essential that each laboratory calculates its own positive/negative cutoff values prior to any routine clinical use of the parameter. This should be a serious consideration when a multicenter study is planned.

Quality control for estrogen and progesterone receptor assay in human breast cancer: the influence of computation methods on intra and interlaboratory variability.

The importance of evaluating receptors for estrogen and progestin in human breast cancer has been pointed out by many authors. In the absence of a reference standard, receptor assays must be controlled by intra and interlaboratory quality control programs. Much interlaboratory variability exists due to non-uniform analytical protocols, non-uniform ligands, intrinsic errors and also errors in computation methods. The goals of our Italian Qualtiy Control Program on Multicenter Trials are to standardize the anaytical procedures and computation methods. Twenty Italian laboratories participated in the Quality Control Program. Each specimen was assayed for steroid receptor content according to the standardized dextran-coated-charcoal method. Data were subjected to computerized analyses by 5 different methods of calculation (Scatchard plot, direct plot, Lineweaver-Burk method, Brunauer-Emmet-Teller analysis, single-point approach). The results were than evaluated to identify intra- and inter-assay variation coefficients and to define other statistical parameters. The authors suggest different calculation methods depending on the specific experimental and/or physiopathological conditions.

Appropriateness of Repeated Execution of Laboratory Examinations: A CDSS Approach

Repetitive laboratory testing has become a well-recognized problem in the practice of medicine, especially in the hospital inpatient setting, since it increases costs and causes patient discomfort. Among the interventions proposed to reduce unnecessary testing, Clinical Decision Support Systems (CDSS) have been shown to be effective. We present the project of a CDSS recommending professionals in real time regarding the appropriateness for repeating laboratory exams, embedded in a Computerized Physician Order Entry at the Azienda Ospedaliero-Universitaria and Azienda Unità Sanitaria Locale of Ferrara, Italy. Test-specific time intervals within which test repetition is redundant are encoded in formal rules, which are applied against the laboratory results done in the past for the patient. The rules-set implemented concerns: clinical chemistry, hematology, coagulation, infectious diseases serology, microbiology, inflammation, cardiac and tumor markers, hormones, autoimmunity, allergology, molecular biology and drug monitoring testing.

Reducing Laboratory Examinations by a Computer-Aided Clinical Decision Support System

Repetitive laboratory testing has become a well-recognized problem in the practice of medicine, especially in the hospital inpatient setting, since it increases costs and causes patient discomfort. Among the interventions proposed to reduce unnecessary testing, Clinical Decision Support Systems (CDSS) have been shown to be effective. We present the project of a CDSS recommending professionals in real time regarding the appropriateness for repeating laboratory exams, embedded in a Computerized Physician Order Entry at the Azienda Ospedaliero-Universitaria and Azienda Unità Sanitaria Locale of Ferrara, Italy. Appropriateness is encoded in test-specific formal rules which are applied against the laboratory results done in the past for a patient, and which eventually trigger an alert meaning that a test repetition is redundant. Both the previous results validation date and quantitative value are considered during rule application. The rules-set implemented concerns: clinical chemistry, hematology, coagulation, infectious diseases serology, microbiology, inflammation, cardiac and tumor markers, hormones, autoimmunity, allergology, molecular biology and drug monitoring testing.