Immunocytochemistry today--problems and practice

Improving evaluation of the distribution and density of immunostained cells in breast cancer using computerized video image analysis

Quantitation of cell density in tissues has proven problematic over the years. The manual microscopic methodology, where an investigator visually samples multiple areas within slides of tissue sections, has long remained the basic ‘standard’ for many studies and for routine histopathologic reporting. Nevertheless, novel techniques that may provide a more standardized approach to quantitation of cells in tissue sections have been made possible by computerized video image analysis methods over recent years. The present study describes a novel, computer-assisted video image analysis method of quantitating immunostained cells within tissue sections, providing continuous graphical data. This technique enables the measurement of both distribution and density of cells within tissue sections. Specifically, the study considered immunoperoxidase-stained tumor infiltrating lymphocytes within breast tumor specimens, using the number of immunostained pixels within tissue sections to determine cellular density and number. Comparison was made between standard manual graded quantitation methods and video image analysis, using the same tissue sections. The study demonstrates that video image techniques and computer analysis can provide continuous data on cell density and number in immunostained tissue sections, which compares favorably with standard visual quantitation methods, and may offer an alternative.

Immunohistochemistry as an important tool in biomarkers detection and clinical practice

The immunohistochemistry technique is used in the search for cell or tissue antigens that range from amino acids and proteins to infectious agents and specific cellular populations. The technique comprises two phases: (1) slides preparation and stages involved for the reaction; (2) interpretation and quantification of the obtained expression. Immunohistochemistry is an important tool for scientific research and also a complementary technique for the elucidation of differential diagnoses which are not determinable by conventional analysis with hematoxylin and eosin. In the last couple of decades there has been an exponential increase in publications on immunohistochemistry and immunocytochemistry techniques. This review covers the immunohistochemistry technique; its history, applications, importance, limitations, difficulties, problems and some aspects related to results interpretation and quantification. Future developments on the immunohistochemistry technique and its expression quantification should not be disseminated in two languages—that of the pathologist and another of clinician or surgeon. The scientific, diagnostic and prognostic applications of this methodology must be explored in a bid to benefit of patient. In order to achieve this goal a collaboration and pooling of knowledge from both of these valuable medical areas is vital

The impact of surgically induced ischaemia on protein levels in patients undergoing rectal cancer surgery

The goal of targeted therapy has driven a search for markers of prognosis and response to adjuvant therapy. The surgical resection of a solid tumour induces tissue ischaemia and acidosis, both potent mediators of gene expression. This study investigated the impact of colorectal cancer (CRC) surgery on prognostic and predictive marker levels. Tumour expression of thymidylate synthase, thymidine phosphorylase, cyclin A, vascular endothelial growth factor (VEGF), carbonic anhydrase-9, hypoxia inducible factor-1α, and glucose transporter-1 (GLUT-1) proteins was determined before and after rectal cancer surgery. Spectral imaging of tissue sections stained by immunohistochemistry provided quantitative data. Surgery altered thymidylate synthase protein expression (P=0.02), and this correlated with the change in the proliferation marker cyclin A. The expression of hypoxia inducible factor-1α, VEGF, and GLUT-1 proteins was also different following surgery. Colorectal cancer surgery significantly impacts on intratumoral gene expression, suggesting archival specimens may not accurately reflect in situ marker levels. Although rectal cancer was the studied model, the results may be applicable to any solid tumour undergoing extirpation in which molecular markers have been proposed to guide patient therapy.

Interpretation and quantification of immunostains

Despite the fact that immunohistochemistry is widely used in routine diagnostic work and is a very common part of scientific reports in pathology and cytology, its standardization still lags behind. Interpretation of immunostains should be based on microanatomic distribution of the staining, proportion of positively stained cells, staining intensity, if relevant, and cutoff levels. These parameters should be shown to be reasonably reproducible and should be clearly defined in publications. Uniformity in the setting of thresholds could probably benefit from interlaboratory control materials containing defined amounts of the target antigen. Reliable and precise quantitative immunohistochemistry requires the use of control materials containing defined amounts of the target antigen and processed alongside the specimen combined with automated computer-assisted microspectrophotometry. Application of these suggestions is hoped to improve standardization and to facilitate communication in the field of immunohistochemistry.

Cholera toxin-induced alteration of the phenotype and behaviour of an ovarian carcinoma cell line, SR8

Cholera toxin (CT) has been reported to cause a variety of effects on several different cell types. Recently, CT has been shown to increase the susceptibility of ovarian carcinoma cells to cytotoxicity mediated by a variety of effector cells (natural killer, lymphokine-activated killer cells and tumour-associated lymphocytes derived from ascites of ovarian cancer patients) of both autologous and allogenic background. In the present study, CT demonstrated several effects on a newly established ovarian carcinoma line (SR8)1 when added to the culture medium at a concentration of 12.5 ng/mL for 2 days. Cholera toxin altered SR8 morphology to a uniform polygonal cellular shape, with less cell dispersion than the non-CT treated cells. Cholera toxin prolonged the population doubling time by approximately 10 h. The CT-treated SR8 cells exhibited reduced epidermal growth factor receptor expression (39 versus 50%), and increased carbohydrate antigen 125 expression (45 versus 2%) in both immunocytochemical and quantitative flow cytometric analyses. These changes in morphology and tumour marker expression were reversible when CT was removed from the culture. The CT-treated SR8 cells showed reduced capacity to generate tumours in female nude mice in comparison with non-CT treated cells, which produce both subcutaneous and intraperitoneal xenografts with local invasion in an animal model. Cytogenetic analysis of the cell line SR8 before and during treatment with CT showed no new clonal rearrangements. The possible mechanisms involved and the influence of CT on the biological behaviour of ovarian tumour cells are discussed.

Electron microscopy for tumour diagnosis: is it redundant?

The histopathological diagnosis of tumours has been transformed by immunohistochemistry. Used with experience and judgement, a panel of antibodies or antisera, combined when necessary with antigen retrieval, will enable the accurate typing of most problematic tumours. This has led many histopathologists to question whether the electron microscope has any residual utility for tumour diagnosis; the machines are large, costly to purchase and maintain, and will accept only minute samples of tissue. The following articles by Mierau and by Eyden, both strong advocates, comment on the current and future role of electron microscopy in tumour diagnosis.

Heat-shock proteins expression in fish central nervous system and its possible relation with water acidosis resistance

The expression of 70 and 60-kDa heat-shock proteins (HSP70 and HSP60) and glial fibrillary acidic protein (GFAP), determined by immunoblotting and immunohistochemical methods, was studied in fish neural tissue; moreover the possible correlation between the expression of these proteins in neural tissue and fish acidosis resistance was also examined. The HSP GFAP content was analyzed in four different teleostean fish species (gourami, carp, goldfish and trout) under control conditions and in carp under experimental conditions to induce HSPs expression. Under control conditions, HSP70 and HSP60 expression was similar in gourami, carp and goldfish, but gourami had the highest acidosis resistance; trout had the lowest HSP70 and 60 expression and lowest acidosis resistance. The HSP expression pattern was mainly neuronal under control conditions. HSP expression was induced in carp and the effect of this induction on acidosis resistance was studied. Two methods were used for HSP induction in carp: acid shock (2 h at 4.5 pH) and heat shock (2 h at 33 degrees C). A high acidosis resistance, although non-significant, was observed after heat pretreatment. An important HSP expression was detected in glial cells after induction. GFAP expression showed no association with acidosis resistance under either control or experimental conditions.

SR8--the establishment and characterisation of a new ovarian carcinoma cell line and xenograft model

A new cell line, SR8, and xenograft model of ovarian carcinoma has been established in this laboratory over the past 20 months from a patient with advanced ovarian cancer. Electron microscopic examination of SR8 cells demonstrated the presence of desmosomes and tonofilaments; SR8 cells expressed epithelial membrane antigen (EMA) and glandular associated cytokeratin, all of these confirmed the epithelial origin of this cell line. In addition, SR8 cells expressed CA125, as did the original ovarian tumour. EGF-R and TP53 expression was identified by immunocytochemistry (ICC) in this line. Nearly all the SR8 cells (93%) expressed HLA-class I antigen while 13.5% expressed HLA-DR. SR8 cells showed near-diploid and -triploid chromosome populations with several clonal and non-clonal rearrangements. Subcutaneous and intraperitoneal xenografting of SR8 cells resulted in invasive tumour production at both sites in 3/4 and 4/4 female nude mice, respectively. These xenografts exhibited similar morphology as that of original tumour and were found to express EMA, cytokeratin, CA125 and TP53. The potential research applications of this cell line are discussed.

What's new in managing health hazards in pathology departments

Health hazards related to activities performed in pathology departments have represented, in recent years, an increasing concern among pathologists and pathology technicians. The major occupational health problems encountered in pathology departments are reviewed. They include biological hazards (tuberculosis, hepatitis, HIV, other infectious diseases), chemical hazards (formaldehyde, xylene(s), aromatic amines, methacrylates, glutaraldehyde, latex) and physical hazards (cut injuries, accidental fires, radiation). Current data suggest that infections (particularly, tuberculosis and hepatitis) still represent the more relevant risk. Exposure to HIV and Creutzfeldt-Jakob agent may be highly harmful but containment measures have been proven to be effective. The actual adverse effects due to chemicals seem to be less alarming than was previously believed. Attaining a safe work environment is an inherent element of good quality assurance management. This task is largely a matter of information, education, organization and common sense. Well-designed premises, efficient equipment and well-trained personnel are the keys to preventing and minimizing hazardous exposures. In order to provide current information that may be used by pathology staff to implement the functional quality of the workplace, organizational and preventive measures are described.

TDM35--a new monoclonal antibody to the XH1 cervical carcinoma cell line. Characterization and immunoperoxidase localization in benign and malignant tissues

The murine monoclonal IgG1 kappa antibody TDM35 was raised against the cervical carcinoma cell line XH1. The antibody recognizes 18.5-66 kDa NCA-like glycoproteins and immunostains a variety of formalin-fixed, paraffin-embedded normal, benign, and malignant tissues. It is of value in the diagnosis of carcinoma of the exocrine pancreas and it identifies foci of squamous and glandular differentiation in other tumours. TDM35 should form a useful addition to a panel of antibodies for the evaluation of epithelial lesions.

XH1--a new cervical carcinoma cell line and xenograft model of tumour invasion, 'metastasis' and regression

A new cell line, XH1, has been derived from an invasive focally keratinising adenosquamous carcinoma of the cervix in a 32 year old patient. It has been maintained in long term monolayer culture for 26 months, and passaged over 100 times (much greater than 300 population doublings). It is aneuploid with a mean chromosome number of 78. Examination using two minisatellite hypervariable DNA probes has shown it to be different from other cell lines maintained in this laboratory and from HeLa. Two sublines, XH1a and XH1b, show marked differences in monolayer culture, growth in soft agar, and xenograft formation. XH1 and XH1a cells readily form subcutaneous xenografts, and lung colonies can be established by their intravenous injection. Subcutaneous injection of XH1b cells results in rapid cell growth for a few days after which the tumour undergoes degeneration and then regresses completely. The XH1 karyotype has many rearranged chromosomes. Parental XH1 cells and both sublines show integration of HPV16 into the genome.

Evaluation of 29 monoclonal and polyclonal antibodies used in the diagnosis of pituitary adenomas. A collaborative study from pathologists of the Club Français de l'Hypophyse

Fifteen polyclonal antibodies (pAbs) and 14 monoclonal antibodies (mAbs) directed against hGH, hPRL, beta hFSH, beta hLH, beta hTSH and alpha-subunit were assessed by five different laboratories on normal and adenomatous pituitary tissues. This study aims at providing pathologists with a selected panel of antisera suitable for diagnosis, and appreciating the interest of the recently introduced mAbs. All the anti-hGH Abs proved to be specific (3 pAbs and 4 mAbs); three mAb out of four gave a few false-negative reactions. Three out of six polyclonal anti-hPRL showed cross-reactivity with hGH; anti-hPRL mAbs gave a strong staining with no false-negativity detected so far. MAbs proved to be more efficient for detecting glycoprotein hormones and alpha subunit than pAbs, which, in several cases, gave widespread cross-reactivity. This lack of specificity could explain the noticeable discrepancies reported so far in the appraisal of gonadotropic and somatoprolactinic adenomas.

The immunoperoxidase localization of tumour markers in ovarian cancer: the value of CEA, EMA, cytokeratin and DD9

Primary tumours from 40 patients with epithelial ovarian cancer, treated at St Thomas's Hospital over a 10-year period, were studied for the immunocytochemical expression of the following tumour markers in formalin-fixed paraffin embedded material: carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), cytokeratin (CAM 5.2), and DD9. An indirect immunoperoxidase staining technique was used. All of the tumours were positive for EMA and CAM 5.2, and 30% of them were positive for both CEA and DD9. The absence of CEA and DD9 may be of value in differentiating between metastatic abdominal adenocarcinomas of ovarian origin and those of gastrointestinal origin, but no indication of prognosis was obtained using these epithelial markers. The strong and widespread staining of all the tumours for EMA suggests that this may be a useful marker for detecting metastatic or recurrent disease by immunoscintigraphy.

Epithelial markers in pancreatic carcinoma: immunoperoxidase localisation of DD9, CEA, EMA and CAM 5.2

Paraffin wax embedded, formalin fixed sections of 22 adenocarcinomas of the exocrine pancreas were stained with four mouse monoclonal antibodies: DD9-E7, an antibody raised against a human pancreatic tumour xenograft; carcino-embryonic antigen (CEA); epithelial membrane antigen (EMA); and cytokeratin (CAM 5.2). An indirect immunoperoxidase technique without enzyme pre-digestion and an affinity-purified sheep anti-mouse peroxidase conjugate were used. All of the tumours were positive for DD9-E7, EMA, and CAM 5.2. Twenty out of 22 were focally positive for CEA and the staining was often weak. As all of these adenocarcinomas were DD9-E7 positive, absence of staining for DD9-E7 in a tumour makes the diagnosis of adenocarcinoma of the exocrine pancreas very unlikely, and this is of value in distinction from endocrine carcinomas with a marked acinar pattern. The weak CEA staining distinguished pancreatic carcinomas from colorectal tumours. Because the distribution of staining for EMA and CAM 5.2 was no different from that previously seen in adenocarcinomas from other sites, these markers are likely to be of limited value in the differential diagnosis of abdominal adenocarcinomas of uncertain origin.