iovannini G

Relationship between cytosol TPS, TPA and cell proliferation

The serological tumor marker tissue polypeptide antigen (TPA) and the more recently identified tissue-specific polypeptide antigen (TPS) have been reported to be indicators of the proliferation rate of the tumor. In the present investigation we compared the cytosol level of the two markers with the proliferative activity of the tumor measured using the 3H-thymidine labelling index. The preliminary results presented here show that higher TLI is associated with lower cytosol levels of both TPA and TPS. TPA and TPS in the cytosol were significantly associated. These findings are in agreement with the previously demonstrated association between high TPA cytosol levels and better prognosis in breast cancer. Further studies are ongoing in order to: 1. confirm these findings in a larger patient series; 2. investigate any possible prognostic indication provided by TPS; 3. evaluate any possible biological meaning of the negative association between TPA/ TPS and TLI in the cytosol of breast cancer.

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.

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.

Immunometric assays of ras and c-erbB-2/neu overexpression in breast cancer: a pilot study.

The expression of the ras and c-erbB2 oncoproteins (p21 and p185, respectively), together with estrogen receptor (ER) and progesterone receptor (PgR) determination, has been retrospectively analyzed in 68 primary breast carcinomas and in 19 normal breast tissue samples. The aims of this study were: a) to explore the association between ras and c-erbB2 expression; b) to evaluate the relationship between ras and c-erbB2 expression and both steroid receptor status and the classical clinical and pathological parameters; and c) to compare two different methods for p185 determination. p185 and p21 were measured by enzyme immunoassay (EIA); p185 was also determined by Western blotting (WB); ER and PgR were assayed by radioligand binding assay. The highest value of p185 in benign breast lesions was used as the threshold to distinguish between positive and negative samples. With this threshold the c-erbB2 oncoprotein was overexpressed in 41.2% (with EIA) and in 50% (with WB) of cancer samples. The concordance rate between the two methods was 79.4. No significant association was found between p21 and p185 levels either in cancer or in normal breast tissue samples. Increasing levels of tumor p21 were associated with a shorter time to recurrence and overall survival. Increasing levels of p185 were associated with a significantly shorter time to recurrence (p185 EIA: p=0.04, p185 WB: p=0.029) and overall survival (p185 EIA: p=0.04, p185 WB: p=0.029).

Estrogen and Progesterone Measurement and its Quality Control in Breast Cancer: A Reappraisal

This article illustrates the two main methods for routine measurement of cytoplasmic estrogen receptor status in neoplastic biopsy. The first is the Dextran Coated Charcoal Technique (D.C.C. Assay) which is still the method of choice in the majority of clinical laboratories for its simplicity, reproducibility and low cost. The second is a more advanced technique based on the specific binding, enzimatically displayed, of commercially available antiestrogen monoclonal antibodies (Enzyme Immuno Assay - ABBOTT). The sui generis characteristics of endocrine sensitivity assessment on tumor tissues and the importance of decision-making connected with the assay justify rigorous quality assurance schemes. The quality control design proposed by the Italian Committee concerned the evaluation of several lyophilized preparations with scalar receptor content; this permits the identification through linear regression analysis of systematic and non-systematic errors. The Italian Committee has currently connected 50 labs from most regions of the country.

Evaluation of p21ras in human breast cancer.

The ras oncogenes are thought to possess potential transforming activity that can be activated either by mutational events or by overexpression of the normal gene. The protein coded for by ras genes, called p21, has been found in tissues by immunoblotting analysis with the monoclonal antibody Yl3-259 (1,2). Computer-assisted image analysis of the resulting autoradiograms has permitted quantitative evaluation of p2lras expression in over 300 samples, comprising human breast carcinomas, normal tissues and benign lesions, Of the carcinomas examined 65% had significantly higher p2lras levels than control tissues and benign lesions. High p21 ras levels were found to correlate with estrogen receptor positivity (ER+), by Spear-