Wet autoclave pretreatment for immunohistochemical demonstration of oestrogen receptors in routinely processed breast carcinoma tissue

Systematic review on hormone receptor testing in breast cancer

Assessment of hormone receptors (estrogen and progesterone) helps to direct therapy for women with breast cancer. Immunohistochemistry is most commonly used to assess hormone receptor status and it is essential that these tests are performed accurately and reliably within and across laboratories. The overall purpose of this guideline is to improve the quality and accuracy of hormone receptor testing and its utility as a prognostic and predictive marker for invasive and in situ breast cancer. Medline, EMBASE, the Cochrane Database of Systematic Reviews, and abstracts from the San Antonio Breast Cancer Symposium were searched. An environmental scan of the internet and of international guideline developers and key organizations was performed. Preanalytic elements such as the collection, fixation, and storage of samples, and analytic elements such as selection of antibodies and scoring methods that seem to offer the best results for immunohistochemical assessment of hormone receptors are presented. Proficiency testing or quality assurance of immunohistochemistry is described.

Cancer care Ontario guideline recommendations for hormone receptor testing in breast cancer

Hormone receptor testing (oestrogen and progesterone) in breast cancer at the time of primary diagnosis is used to guide treatment decisions. Accurate and standardised testing methods are critical to ensure the proper classification of the patient's hormone receptor status. Recommendations were developed to improve the quality and accuracy of hormone receptor testing based on a systematic review conducted jointly by the American Society of Clinical Oncology/College of American Pathologists and Cancer Care Ontario's Program in Evidence-Based Care. Evidence-based recommendations were formulated to set standards for optimising immunohistochemistry in assessing hormone receptor status, as well as assuring quality and proficiency between and within laboratories. A formal external review was conducted to validate the relevance of these recommendations. It is anticipated that widespread adoption of these guidelines will further improve the accuracy of hormone receptor testing in Canada.

Estrogen receptor antibody incubation time and extent of immunoreactivity in invasive carcinoma of the breast: the importance of optimizing antibody avidity

We noticed that the percentage and intensity of estrogen receptor (ER) antibody (Ab) AB ER 1D5 immunohistochemical (IHC) staining was altered by Ab incubation time and the type of chromogen detection system in invasive breast carcinomas. We studied the impact of these 2 factors on Ab ER 1D5 immunoreactivity. Serial sections from 22 strongly ER-positive invasive breast carcinomas were immunohistochemically stained with Ab clone ER 1D5 using 3 IHC protocols. One IHC protocol used a 12-hour Ab incubation and a supersensitive, labeled streptavidin-biotin chromogen detection system (12 h-Standard), the second IHC protocol used a 2-hour Ab incubation and a supersensitive, labeled streptavidin-biotin chromogen detection system (2 h-SS), and the third protocol used a 2-hour Ab incubation and a polymer-based detection system (2 h-Env). Twenty identical fields on each slide stained with each IHC protocol were evaluated and staining was quantified using image analysis. The mean staining percentages using the 12 h-Standard, 2 h-SS, and 2 h-Env IHC staining protocols were 89%, 72%, and 47%, respectively (P<0.001). Three of the 22 cases (14%) were ER negative (<10% stained area) with the 2 h-Env IHC protocol. Stain intensity was significantly stronger with the 12 h-Standard Ab incubation IHC protocol than either 2-hour Ab incubation protocol (P<0.001). Twelve cases stained with 2-hour Ab incubation IHC protocols had weak visually seen staining: 7 were Allred total score 2 (ER negative) and 5 were Allred total score 3. Ab ER 1D5 avidity is directly related to factors that impact electrostatic forces, one of which is Ab incubation time. Standard automated stainer Ab incubation times of less than 1 hour may be of insufficient duration and result in artificially low levels of ER immunoreactivity. The chromogen detection system in association with the ER 1D5 Ab also alters levels of immunoreactivity. Optimization of IHC staining protocols should include evaluating the Ab incubation time and chromogen detection system. These factors can substantially alter the extent and intensity of ER IHC staining.

Comparison of Immunoexpression of 2 Antibodies for Estrogen Receptors (1D5 and 6F11) in Breast Carcinomas Using Different Antigen Retrieval and Detection Methods

The importance of in situ immunodetection of hormone receptors for therapy planning and prognostic evaluation in patients with breast carcinoma is well established. Sensitive detection methods are of utmost importance, especially in poorly fixed tissues, which are not uncommon in routine pathologic practice. The purpose of the present study is to compare immunoexpression of estrogen receptors in 20 cases of invasive ductal carcinoma using two antibodies, 1D5 and 6F11, and to verify the effect of different antigen retrieval solutions and detection systems. Immunoperoxidase was performed on paraffin sections using 1D5 and 6F11 as primary antibodies. Heat-induced antigen retrieval was performed using citrate buffer (pH 6.0) or Tris-EDTA buffer (pH 8.9). Detection was achieved using the following systems: EnVision, EnVision Plus, and labeled streptavidin-biotin peroxidase complex. Reaction was semiquantified from 0 to 4. There were no differences between the two markers, 1D5 and 6F11, except when 6F11 was used with EnVision and citrate buffer, in which case weaker reactivity was observed. Only in this combination (6F11/EnVision) was EDTA buffer significantly better than citrate. Labeled streptavidin-biotin peroxidase complex presented the best results, followed by EnVision Plus.

Computer-assisted immunocytochemical determination of breast cancer steroid receptors. Frozen sections vs paraffin sections

Previously we have demonstrated that determination of oestrogen (ER) and progesterone (PR) receptors by immunocytochemical assay (ICA) on frozen sections (FS) and cytological smears with image analysis is effective for evaluating steroid receptors. The aim of this study was to determine concordance between ER and PR assessed by ICA on FS and paraffin sections (PS) both evaluated by image analysis. There were 115 breast carcinomas selected. For all cases, ER and PR determination was performed on FS and PS. Computer-assisted image analysis was performed using CAS 200. Results were expressed as percent positive area of neoplastic nuclei compared with total nuclear area of the examined neoplastic cells. Good correlation was demonstrated for both ER (r=0.759; concordance=83.4%) and PR (r=0.800; concordance=87.8%). The unexpected relatively low concordance for ER led to further investigations. We divided the 115 cases in two groups. The first group included specimens from our hospital; the second group specimens from suburban hospitals. In the first group there was better correlation for both ER (r=0.897) and PR (r=0.915) with a concordance of 91.5% and 93.6%, respectively. In the second group, correlation was worse for both ER (r=0.724) and PR (r=0.708), with a concordance of 77.9% and 83.9% respectively. From analysis of discordant cases we conclude that reduction in correlation and concordance with increased false negative cases in group 2 are probably due to delayed fixation. Our data suggest that ICA with automated image analysis is efficient in evaluating ER and PR on paraffin section only when the tumour samples are correctly fixed.

Clinical relevance of immunohistochemical expression of p53-targeted gene products mdm-2, p21 and bcl-2 in breast carcinoma

The present study was designed to investigate the clinical/prognostic relevance of immunohistochemical expression of p53-targeted genes mdm-2, p21WAF1 and bcl-2 alone and in combination with p53 for the indirect assessment of p53 gene status in breast cancer. 141 archival breast carcinomas were immunostained, and the putative mutational status of the p53 gene was defined in 21 of them, as a control for immunohistochemistry, using the polymerase chain reaction single-strand conformational polymorphism (PCR-SSCP) analysis. Genetic changes of p53 correlated significantly with p53 protein overexpression (p = 0.01) but did not do so with any of the related molecules. Immunohistochemical p53 status was directly correlated with mdm-2 (p = 0.0001), p21 (p = 0.0004) and inversely with bcl-2 (p = 0.005) expression. bcl-2 proved to be an independent marker of prognosis, p53 only in the group of node-positive carcinomas, whereas bcl-2-/p53+ tumours revealed the worst prognosis. Mdm-2 and p21 expression was of prognostic significance neither alone nor in combination. We conclude that the detection of down-stream regulators of p53 does not increase the efficacy of immunohistochemistry in assessing the functional status of p53 in breast cancer; however, their combined analysis may help to select subgroups of patients at the extremes of risk for recurrence, or those with greater chances for survival.

Significance of Wet Autoclave Pretreatment in Immunohistochemistry

Until recently the only way to rescue masked epitopes in routinely processed surgical pathological material was enzymatic digestion. The use of heat for antigen retrieval, first by microwave irradiation, represents an important breakthrough in immunohistochemistry. With the acceptance of microwave oven pretreatment, various modified techniques and alternative heating methods have also been proposed. Wet autoclave pretreatment for tissue proteolysis is a highly reliable alternative to the microwave antigen retrieval technique. It provides uniform heating of the slides, hence an even enhancement of staining intensity in a variety of formalin-sensitive antigens, and it also offers consistent interlaboratory results. The method has been introduced in routine diagnostic immunohistochemistry for the detection of estrogen- and progesterone receptors, L26-, Ki-67- and bcl-2 antigens and variable types of cytokeratins (1/5/10/11, 8, 13, 19). Experimentally, wet autoclaving can be used very successfully for the immunophenotyping of p53 and mdm2 expression, for the detection of adhesion molecules (CD44, integrins) and some anti-inflammatory molecules (annexins), among others. It has produced a substantial improvement in the visualisation of silver-stained nucleolar organizer regions- associated proteins (AgNORs) in routine paraffin sections and along with modified silver staining and standardized AgNOR parameters assessed by image analysis. Wet autoclaving-based AgNOR staining has been proposed by a European multicentric study group as the standardized method for AgNOR analysis in archival material.

Different genetic pathways in the evolution of invasive breast cancer are associated with distinct morphological subtypes

Invasive breast cancer shows a wide range of morphological differentiation, associated with differences in prognosis, but as yet, the underlying genetic mechanisms cannot be accounted for. In order to establish a model of the possible progression from the different subtypes of ductal carcinoma in situ (DCIS) to invasive breast cancer, 77 selected cases of invasive breast cancer representing distinct morphological subtypes were investigated by means of comparative genomic hybridization (CGH). There was a high degree of genetic homology between tubular and tubulo-lobular carcinoma and well-differentiated DCIS, and between ductal invasive carcinoma G3 and poorly differentiated DCIS. Highly differentiated invasive breast cancers were characterized by a loss of 16q and a low average number of aberrations per case. In high-grade tumours, losses of this chromosomal region were seen with a much lower frequency in cases with evidence of an aneuploid tumour status. These data demonstrate the close genetic similarity of well-, intermediately, and poorly differentiated DCIS and distinct morphological types of invasive breast carcinoma, providing further evidence that DCIS is a direct precursor lesion of invasive breast cancer and that various evolutionary genetic pathways exist.

Immunohistochemical detection of progesterone receptors in archival breast cancer

The progesterone receptor (PR) is an important marker of response to endocrine agents in breast cancer. Immunohistochemical demonstration of PR in formalin fixed tissue has previously proved difficult, and heat pretreatment is considered necessary to retrieve the antigen. There are few data on the effectiveness of autoclaving in unmasking PR, however, and it is not known whether all PR epitopes are equally unmasked. The objectives of this study were to compare the efficacy of autoclaving and microwaving to retrieve PR antigen in archival breast tumors, to determine whether there is an epitope-dependent variability in the pretreatment required, and to examine different slide types and adhesives to reduce the problem of section loss frequently associated with these procedures. Paraffin embedded sections were cut at 2 or 4 microm, mounted onto various slide types with or without the addition of adhesive, and heat pretreated prior to immunoperoxidase staining. Whereas PR immunoreactivity was clearly demonstrated in tissue after both autoclaving and microwaving, autoclaving produced a significantly stronger staining intensity under the conditions used in this study. The duration of autoclaving required to reveal PR fully differed for different epitopes examined. In the absence of heat pretreatment, PR was not detected. Section retention was improved by the use of adhesives and by cutting tissue at 2 microm. Maximum retention was obtained using positively charged slides coated with Mayer albumen adhesive. We conclude that for maximal tissue preservation autoclave pretreatment is the preferred method of PR antigen retrieval from archival breast tumors, that there is epitope-dependent variability in pretreatment required, and that section loss during this procedure can be minimized by choice of slide type, the use of adhesive, and by cutting sections at 2 microm.

A comparison of methods for heat-mediated antigen retrieval for immunoelectron microscopy: demonstration of cytokeratin No. 18 in normal and neoplastic hepatocytes

Postembedding antigen retrieval is a well established technique for immunoelectron microscopy; however, many antigens cannot be detected without additional unmasking procedures. This study was undertaken to determine whether microwave oven heating, autoclaving, and pressurized boiling, which are well recognized methods of antigen retrieval for light microscopy, and simple boiling can also be used in electron microscopy. We investigated neoplastic and normal hepatocytes using a commercially available mouse monoclonal antibody against cytokeratin NO. 18 (CK 18). The tissue was fixed in paraformaldehyde/glutaraldehyde and embedded in Lowicryl K4M at -40 C. Ultrathin sections in various buffers were exposed to heat using one of four methods or to pronase at 37 C before incubation with the primary antibody. The secondary antibody was gold-labeled goat anti-mouse antibody. Sections that were not heat-treated remained unlabeled, but heat-treated sections showed immunoreactivity located mainly at the cytoplasmic periphery. Some of the gold particles lay in direct or loose association with intermediate filaments, some were seen in the area of desmosomes, and some did not appear related to any structures. No difference in immunostaining was found among the four methods of heat treatment. The citrate buffer, pH 6.0, and 10 mM EDTA, pH 8.0, generated the best labeling results.

Unaltered strong immunohistochemical expression of CD44-v6 and -v5 isoforms during development and progression of oral squamous cell carcinomas

The present study was designed to immunolocalize CD44-v6 and -v5 isoforms in normal, dysplastic and malignant oral mucosa as well as in primary and metastatic oral squamous cell carcinomas. Routinely formalin-fixed and paraffin-embedded tissues of 100 oral carcinoma patients were immunohistochemically investigated following wet autoclave antigen retrieval. Both CD44-v6 and -v5 epitopes were uniformly strongly expressed on the cell surface of basal and intermedial epithelial cells of normal and dysplastic mucosa and in all primary and metastatic squamous cell carcinomas with the exception of end-differentiated keratinizing cells. Our results strongly suggest that CD44-v6 and -v5 isoform expression is not altered during development and progression of oral carcinomas. Thus, they seem to be irrelevant factors in the prediction of prognosis in this type of cancer.

Standardized AgNOR analysis: its usefulness in surgical oncology

Recent improvements both in the staining quality and computer-aided quantitation of silver-stained nucleolar organizer region (AgNOR)-associated proteins offer the possibility to reliably investigate these proteins on routinely processed archival material. This article deals with the historical background, the recent introduction of a standardized quantitation, the clinical relevance, and future perspective for AgNOR evaluation. It is specifically emphasized that AgNOR analysis after both standardized staining and computer-aided quantitation (as recommended by the Committee on AgNOR Quantitation of the European Society of Pathology) is now regarded as the gold standard whenever routinely formalin-fixed and paraffin-embedded material is investigated.