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At least 181 records · Page 10Linked to original sources

PubMed1996

Immunoglobulin light chain staining in paraffin-embedded tissue using a heat mediated epitope retrieval method.

We have compared light chain immunohistochemistry in reactive lymphoid tissue and a series of paraffin-embedded B-cell lymphomas using standard trypsin digestion with a heat mediated epitope retrieval method. Fifty-seven B-cell lymphomas (18 high grade, 29 low grade and 10 cases of nodular lymphocyte predominance Hodgkin's disease), two reactive lymph nodes and eight tonsils fixed for known times between 12 h and 2 years were studied. Paraffin-embedded tissue was stained with polyclonal anti-kappa and anti-lambda antibodies. For each antibody staining was performed on two sections, one treated with trypsin digestion and one with microwave heating. Sections were scored from 0 to + + + with 0 representing poor staining and + + + excellent staining. A score of ++ was considered satisfactory. Light chain restriction was recorded if present. Satisfactory staining was obtained in 34/59 cases using trypsin digestion and 56/59 cases using heat retrieval. Light chain restriction was demonstrated in 32/57 (56%) B-cell lymphomas using trypsin digestion and 52/57 (91%) using heat retrieval. Satisfactory staining was obtained in tonsils fixed for up to 48 h using trypsin digestion and up to 2 years using heat retrieval. We have shown that for light chain immunostaining a heat mediated epitope retrieval method produces more consistent and satisfactory results and is effective over a greater range of fixation times than traditional trypsin digestion.

Epitopes↗

PubMed1990

Ploidy of smooth muscle tumours: retrospective image analysis study of formalin fixed, paraffin wax embedded tissue.

The feasibility of using an image analyser, the CAS 100, to assess the ploidy of smooth muscle tumours on formalin fixed paraffin wax embedded tissue was assessed. Various different methods of assessment were compared. A paraffin wax block of 15 leiomyomata and 13 leiomyosarcomata yielded serial sections of 3 microns, 5 microns, and 7 microns and a cytospin preparation (from a 50 micron section). Sections and cytospin preparations were stained with Feulgen and quantified using the CAS 100. The suitability of lymphocytes, previously suggested to be unsuitable as control cells in tissue sections due to the compact nature of their DNA, was assessed in sections and cytospin preparations and compared with endothelial cells, the standard alternative, on the same slide. Despite having a mean nuclear area of only 18.5 microns 2 in sections lymphocytes had a similar diploid peak--that is, 4.1 pg--to endothelial cells (mean nuclear area 39 microns 2). A comparison of 3 microns, 5 microns, and 7 microns sections showed 5 microns to be the optimal thickness. Cytospin preparations yielded histograms of superior quality than those from tissue sections. All 15 leiomyomata had a 5C exceeding rate of less than 0.3%. Ten of 11 histologically malignant tumours had a 5C exceeding rate of more than 5% (mean 14%) in sections and cytospins. Two leiomyosarcomata that had arisen in the lower gastrointestinal tract had a mitotic rate of less than or equal to 1/10 per high power fields and yielded histograms similar to those of the leiomyomata. It is concluded that formalin fixed, paraffin wax embedded tissue can be used for DNA quantification by image analysis; that tissue sections yield poorer results than cytospin preparations; that lymphocytes are reliable control cells in cytospin preparations; and that a population of cell greater than 5C is seen in 90% of leiomyosarcomata.

Cell Separation↗

PubMed2002

Detection and differentiation of North American and European genotypes of porcine reproductive and respiratory syndrome virus in formalin-fixed, paraffin-embedded tissues by multiplex reverse transcription-nested polymerase chain reaction.

North American and European genotypes of porcine reproductive and respiratory syndrome virus (PRRSV) were distinguished in formalin-fixed, paraffin-embedded tissues from PRRSV-infected pigs by multiplex reverse transcription-nested polymerase chain reaction (RT-nPCR). A method based on xylene deparaffinization followed by proteinase K digestion yielded RNA of quality for reliable and consistent RT-nPCR analyses. The PRRSV nucleic acid was detected in lung, mediastinal lymph node, tonsil, and liver samples from pigs inoculated with North American strain virus, European strain virus, or both North American and European strains. All 30 archival formalin-fixed, paraffin-embedded lung tissues from pigs naturally infected with PRRSV were positive for PRRSV by RT-nPCR amplication and gave a pattern that corresponded to the North American genotype. Multiplex RT-nPCR could be applied successfully to formalin-fixed, paraffin-embedded tissues for the detection and differentiation between North American and European genotypes of PRRSV.

Animals↗

PubMed1995

Comparison of flow and image cytometry for DNA content analysis of fresh and formalin-fixed, paraffin-embedded tissue in breast carcinoma.

DNA ploidy and S-phase fraction are considered to be prognostic variables in breast carcinoma. DNA content of 35 cases of breast carcinoma of varying histologic types and nuclear grades was analyzed by flow cytometry and image analysis in both fresh and formalin-fixed, paraffin-embedded tissue. Fresh cell and deparaffinized nuclear suspensions were used for flow cytometry. Fresh and deparaffinized tumor tissue samples were used for image analysis. The results of analysis for DNA ploidy, DNA index of DNA aneuploid Go/G1 peaks, and S-phase fraction were compared in different tissue preparations for both techniques. The two techniques produced comparable DNA ploidy results with both fresh and formalin-fixed, paraffin-embedded tissue. Sensitivity for detection of DNA aneuploidy was somewhat greater by image analysis, particularly in deparaffinized tissue. There was 89% agreement in detection of DNA aneuploidy by flow cytometry in fresh and paraffin-embedded, formalin-fixed tissue; the coefficients of variation of the DNA diploid Go/G1 peaks were much wider in the latter. In image analysis there was 91% agreement between fresh and fixed specimens. Agreement between the flow cytometry and image analysis in fresh specimens was 91%; in deparaffinized nuclear suspensions it was 94%. There is a high degree of correlation between the values of DNA index of DNA aneuploid Go/G1 peaks; the estimates of S-phase fraction are much more variable. Results also show a good correlation of the DNA ploidy with the nuclear grades.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma, Mucinous↗

PubMed1993

Comparison of pepsin and trypsin digestion on paraffin-embedded tissue preparation for DNA flow cytometry.

Preparation with enzymes plays an important part in obtaining good results in cellular DNA content measurements from paraffin-embedded tissue using flow cytometry. Therefore, we have compared two groups of DNA histograms obtained with pepsin (Hedley method) and trypsin digestion (Schutte method). Samples of five tumor types were compared: eight lung, seven breast, five thyroid, seven stomach, and six colon cancer cases. All samples were stained with propidium iodide (PI). The incidence of DNA aneuploidy determined by the Schutte method indicated a higher ratio in four tumor types than that determined by the Hedley method. Concerning the coefficient of variation (CV) used to estimate the quality of the DNA histogram, the diploid G1 peak determined by the Schutte method produced a smaller CV in five tumor types than did the Hedley method. This Schutte method had especially good results in lung and thyroid cancer. Furthermore, the amount of debris (background) determined by the Schutte method indicated a decrease in four tumor types compared with the Hedley method. In cell-cycle analysis of ten DNA diploid cases, DNA histograms by the Hedley method showed an increased S-phase fraction due to an overlapping of debris and aggregated cells. These results indicate that preparation by trypsin digestion is a method superior to pepsin digestion when the sample from paraffin-embedded tissue is stained with PI for the purpose of DNA content measurement.

Breast Neoplasms↗

PubMed1991

Growth fraction estimation of malignant lymphomas in formalin-fixed paraffin-embedded tissue using anti-PCNA/Cyclin 19A2. Correlation with Ki-67 labeling.

The immunohistochemical detection of PCNA/Cyclin, a nuclear protein associated with cell proliferation, represents a potentially useful tool for the study of tumor proliferative activity. Previous studies investigating the reactivity of anti-PCNA/Cyclin monoclonal antibody 19A2 have not clearly defined the population of proliferating cells with which 19A2 reacts in tissue sections. The authors describe a method for detection of PCNA/Cyclin in formalin-fixed, paraffin-embedded tissue using a routine biotin-streptavidin immunohistochemical system that employs an anti-IgM, mu-chain-specific second-stage antibody. The authors used this method to study the proliferative activity of 24 malignant lymphomas, consisting of 12 low-grade lymphomas (LGLs) and 12 intermediate-grade lymphomas (IGLs), and five reactive tonsils. 19A2 data was compared with Ki-67 labeling in frozen sections in the same group of cases. 19A2 provided easily detectable nuclear staining of proliferating cells with reactive cells demonstrating varying intensity of staining, this latter finding most likely due to the varying nuclear concentration of PCNA/Cyclin protein during the cell cycle. In tonsils, 19A2 reacted with germinal center cells and basal keratinocytes. In the malignant lymphomas, there was good correlation between 19A2 and Ki-67 data (r = 0.90, P less than 0.001). The subgroup of LGLs showed a mean PCNA/Cyclin of 26% and a mean Ki-67 of 28%. In the subgroup of IGLs, mean PCNA/Cyclin = 54% and mean Ki-67 = 59%. These results indicate that 19A2 detects a fraction of proliferating cells that is similar to that detected by Ki-67, ie, the growth fraction, and that 19A2 is a reliable marker of proliferative activity in uniformly handled, formalin-fixed, paraffin-embedded tissue.

Antibodies↗

PubMed2001

An immunohistochemical method that differentiates Cryptococcus neoformans varieties and serotypes in formalin-fixed paraffin-embedded tissues.

An immunohistochemical method for determining the variety of Cryptococcus neoformans in formalin-fixed paraffin-embedded tissues was developed using mAbs 471, 302 and CRND8. The method was validated primarily using veterinary patients for which both formalin-fixed lesions and a cultured isolate were available. L-Canavanine glycine bromothymol blue (CGB) agar and the 'Crypto-Check' kit were used to determine the variety and serotype, respectively, of cultured isolates. Immunohistochemistry accurately predicted the C. neoformans variety in all tissue specimens. The CGB agar method of determining C. neoformans variety gave the same result as immunohistochemistry for 30/31 specimens. For the single discordant isolate, the serotype, random amplification of polymorphic DNA profile, microscopic and colony morphology all supported the immunohistochemical staining pattern in suggesting C. neoformans var. gattii; however, the CGB agar result was at variance. Of the C. neoformans var. neoformans cases, immunohistochemistry was congruent with variety for 13/13 cases and with serotyping for 10/13 cases. The three discordant cases were classified as having some serotype D reactivity by immunohistochemistry, but were considered to be serotype A using the Crypto-Check kit. This new method should prove a valuable epidemiological tool in studies of cryptococcosis, especially in the veterinary setting where archival tissue specimens may exist but corresponding mycological data is typically absent. The versatility of this method will expand in the future as other monoclonal antibodies with different specificities are developed.

Antibodies, Monoclonal↗

PubMed1999

Quantitation of intraepidermal T-cell subsets in formalin-fixed, paraffin-embedded tissue helps in the diagnosis of mycosis fungoides.

Differentiation between mycosis fungoides (MF) and cutaneous inflammatory processes can usually be made on clinical and histologic grounds. In difficult cases, immunohistochemical studies can be helpful since MF infiltrates usually contain a predominance of CD4+ lymphocytes, while most inflammatory lesions usually have a mixture of CD4+ and CD8+ lymphocytes. However, this determination has traditionally required the use of frozen tissue, thus severely limiting its usefulness. Recently, antibodies that differentially label CD4+ and CD8+ lymphocytes in formalin-fixed, paraffin-embedded tissue have become available (OPD4 and C8/144B respectively, DAKO (Carpinteria, CA, USA). This study tests the utility of these antibodies in the pathologic diagnosis of MF and inflammatory lesions with significant exocytosis. In 9 cases of MF for which both frozen and fixed tissues were available for comparison, the OPD4+ cell count in fixed tissue was significantly lower than the Leu-3a+ cell count in frozen tissue. Also, the C8/144B+ cell count in fixed tissue was higher than the Leu-2a+ cell count in frozen tissue, although this difference was not significant statistically. In a larger series for which only fixed tissue was available, epidermal CD4:CD8 ratios were significantly greater in 23 MF cases (mean 4.0+/-4.76) than in 35 inflammatory cases (mean 0.6+/-0.42; p = 0.001). Thus, although the studied antibodies appear to detect different epitopes in frozen versus paraffin-embedded tissue, demonstration of an elevated CD4:CD8 ratio in fixed tissue supports the diagnosis of MF, and is a helpful adjunct to routine histopathology.

Aged↗

PubMed1991

Estrogen receptor in primary breast cancer estimated in paraffin-embedded tissue. A study of its usefulness compared to dextran-coated charcoal assay.

Estrogen receptor (ER) was estimated immunohistochemically in formalin-fixed and paraffin-embedded tissue from the primary breast cancer in 349 postmenopausal patients with a high risk of recurrence and compared with the results of dextran-coated charcoal assay. There was a highly significant correlation between the ER classification obtained by the two methods (p less than 10(-6)). Patients ER positive according to immunohistochemical estimate had a significantly longer disease-free survival (p less than 0.001) and survival (p less than 0.001) than ER negative patients. The DCC assay showed an advantage of ER positive patients of the same magnitude. The patients, who were followed for a median of 86 months, were a subset of 1,700 patients participating in the Danish Breast Cancer Cooperative Group's randomized trial of adjuvant tamoxifen (TAM) treatment. In the presently analyzed subset of patients there were no statistically significant difference in disease-free survival (p = 0.52) or survival (p = 0.54) between patients who received adjuvant TAM and the controls. The same was true for receptor-defined subgroups regardless if the ER receptor was estimated in paraffin-embedded tissue or by the dextran-coated charcoal method. The analyzed subset might have been too small for demonstrating a positive effect of adjuvant TAM treatment.

Breast Neoplasms↗

PubMed1994

Production of two monoclonal antibodies (FB1 and FB21) useful for the identification of human B lymphocytes in formalin-fixed, paraffin-embedded tissues.

Two monoclonal antibodies (FB1 and FB21) reactive in formalin-fixed, paraffin-embedded tissue sections are reported in this paper. FB1 and FB21 recognize a cytoplasmic antigen and a surface antigen of B cells, respectively. FB1 reacts with mantle zone (MZ) B cells, germinal centre (GC) cells, and marginal zone (MrZ) B cells, but not with T cells in lymphoid tissues. FB21 reacts with MZ B cells, GC cells in lymphoid tissues, and T cells of peripheral blood, but not with MrZ B cells in the spleen. Neither monoclonal antibody (MoAb) reacts with monocytes, granulocytes, or plasma cells. FB1 reacted with all the B-cell lymphomas tested and with CD20-positive Reed-Sternberg cells in two of five cases of Hodgkin's disease, but not with multiple myelomas or T-cell lymphomas. FB21 reacted with B-cell lymphoma in 20 of 22 cases, but not with multiple myelomas, T-cell lymphomas, or Reed-Sternberg cells of Hodgkin's disease. Immunoprecipitation studies revealed that FB1 recognizes the same two polypeptide chains that are recognized by L26 and is a member of the CD20 antibody cluster. FB21 was thought to recognize a sialic acid-dependent carbohydrate epitope and this was confirmed at the Fifth International Conference on Human Leukocyte Differentiation Antigens (Boston, 1993). FB21 did not react with splenic MrZ B cells and was different from the pan B markers reported previously [CD20 (L26), CD45RA (MB1), and CD74 (LN-2)]. FB21 recognizes a subset of B cells and appears to be closely related to CD75/76 antibodies. FB1 and FB21 are useful MoAbs for the diagnosis and analysis of B-cell lymphomas.

Animals↗

PubMed2004

Development of nested RT-PCR for the detection of swine hepatitis E virus in formalin-fixed, paraffin-embedded tissues and comparison with in situ hybridization.

Swine hepatitis E virus (HEV) was detected in formalin-fixed, paraffin-embedded tissues from naturally infected pigs by nested reverse transcription-polymerase chain reaction (RT-PCR). The results for seminested RT-PCR were compared with those determined by in situ hybridization. The results obtained show that use of xylene deparaffinization, digestion with proteinase K followed by nested RT-PCR is a reliable detection method. Swine HEV nucleic acid was detected in formalin-fixed, paraffin-embedded hepatic tissues from 40 pigs. Distinct positive signals for swine HEV were obtained in the same hepatic tissues by in situ hybridization. Swine HEV nucleic acid was localized to the cytoplasm of hepatocytes and had a granular staining pattern. The rate of agreement between nested RT-PCR and in situ hybridization for the detection of swine HEV in formalin-fixed, paraffin-embedded hepatic tissues was 100%.

Animals↗

PubMed2004

Detection of t(14;18) in follicular lymphoma by dual-color fluorescence in situ hybridization on paraffin-embedded tissue sections.

We studied the incidence of t(14;18)(q32;q21) in 54 patients with follicular lymphoma (FL) by dual-color fluorescence in situ hybridization on paraffin-embedded tissue sections (tissue-FISH) using probes for BCL2 and immunoglobulin heavy chain (IGH) genes. The t(14;18) was detected in 28 (56%) of 50 patients, who were successfully analyzed. On the other hand, BCL2 protein expression was detected in 45 (83%) of 54 patients evaluated by immunohistochemical staining. There was a discrepancy between t(14;18) and BCL2 expression. The absence of t(14;18) was associated with disease-free survival (P=0.02). There was no statistical difference, however, in overall survival and failure-free survival between the t(14;18)-positive and -negative groups. Tissue-FISH should be of great value to detect t(14;18) in FL because this method enabled us to demonstrate specifically t(14;18)-positive individual cells in neoplastic follicles on paraffin-embedded tissue sections. Furthermore, tissue-FISH can be applied to small specimens obtained from endoscopic biopsy or specimens obtained more than 10 years ago. We validated the usefulness of tissue-FISH as a diagnostic procedure and retrospective meta-analysis for malignant lymphoma.

Adult↗

PubMed1992

DNA quantification of squamous cell carcinoma of the oesophagus by flow cytometry and cytophotometric image analysis using formalin fixed paraffin embedded tissue.

This is the first comparative study of DNA quantification of oesophageal squamous cell carcinoma by flow cytometry (FCM) and image cytometry (ICM) using formalin fixed paraffin embedded tissue. The potential advantages of ICM include the identification of a reliable control cell population; avoidance of non-tumour stromal and inflammatory cell nuclei, nuclear fragments, degenerate cell nuclei and doublets, triplets etc., which are not possible with FCM using archival tissue. Twenty-eight cases, all of the same stage (stage 2a) and similar grade (well or moderately differentiated) were analysed. The cases were separated into two groups, those that had succumbed to tumour in less than 18 months (group A) and those that were tumour free at least 18 months post-resection (group B). Using ICM all 28 tumours yielded interpretable histograms by comparison to 25 of 28 using FCM. Aneuploidy was identified in 100% of cases in group A using ICM (in comparison to 73% by FCM) and in 73% of group B using ICM (in comparison to 44% by FCM). Any tumour aneuploid by FCM was also aneuploid by ICM. Nine cases aneuploid by ICM were euploid by FCM. The mean 5C exceeding rate (% of cells whose nuclei contain a DNA mass equivalent to > 5 sets of 23 chromosomes) was 21% in group A and 14% in group B (P < 0.01). Euploidy was confined to tumours of those patients disease free for more than 18 months. The conclusions of this study are that: firstly, ICM is superior in its yield of interpretable histograms to FCM using formalin fixed paraffin embedded tissue; secondly, ICM is more sensitive in the identification of aneuploid stemlines than FCM; and thirdly, euploid tumours (as detected by ICM) appear to have a better prognosis than aneuploid tumours of similar stage and grade.

Adult↗

PubMed2003

Identification of tissue-embedded ascarid larvae by ribosomal DNA sequencing.

Polymerase chain reaction (PCR) was applied to identify tissue-embedded ascarid nematode larvae. Two sequences of the internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA), ITS1 and ITS2, of the ascarid parasites were amplified and compared with those of ascarid-nematodes registered in a DNA database (GenBank). The ITS sequences of the PCR products obtained from the ascarid parasite specimen in our laboratory were compatible with those of registered adult Ascaris and Toxocara parasites. PCR amplification of the ITS regions was sensitive enough to detect a single larva of Ascaris suum mixed with porcine liver tissue. Using this method, ascarid larvae embedded in the liver of a naturally infected turkey were identified as Toxocara canis. These results suggest that even a single larva embedded in tissues from patients with larva migrans could be identified by sequencing the ITS regions.

Animals↗

PubMed1998

Evaluation of PCR in detection of Mycobacterium tuberculosis from formalin-fixed, paraffin-embedded tissues: comparison of four amplification assays.

We compared the sensitivities and specificities of four nested PCR assays for the detection of Mycobacterium tuberculosis from formalin-fixed, paraffin-embedded tissues. Thirty-seven autopsy samples from human immunodeficiency virus-positive patients were analyzed: 15 were M. tuberculosis positive, 11 served as negative controls, and 11 were Ziehl-Neelsen positive without cultural confirmation of M. tuberculosis. Three genomic sequences (mtp40, 65-kDa antigen gene, and IS6110) with different molecular masses and numbers of repetitions within the M. tuberculosis genome were targeted. On the IS6110 sequence, two fragments of different sizes (106 and 123 bp, respectively) were amplified with two separate pairs of primers. The highest sensitivity rates were obtained by amplifying the highly repetitive IS6110 insertion sequence, and the different primers tested showed a sensitivity ranging from 80 to 87%. Amplification of the large 223-bp fragment of the mtp40 sequence present in a single copy in the M. tuberculosis genome yielded a high rate of false-negative results, ranging from 66 to 80%. A poor sensitivity (from 47 to 60%) was also shown by PCR amplification of the 142-bp 65-kDa antigen gene. All the PCRs except that for the 65-kDa antigen gene showed a specificity of 100%. Moreover, different results were obtained with different dilutions of DNA, and DNA concentrations of 1 and 3 microg yielded the highest sensitivities depending upon which protocol was used. Application of the PCRs to the Ziehl-Neelsen-positive, culture-negative samples confirmed the sensitivities of the PCRs obtained with the control samples. In conclusion, PCR can successfully be used to detect M. tuberculosis from paraffin-embedded tissues and can be particularly useful in the validation of a diagnosis of tuberculosis in clinical settings in which the diagnosis is uncertain. However, the efficacy of PCR strictly depends on several amplification parameters such as DNA concentration, target DNA size, and the repetitiveness of the amplified sequence.

Evaluation Studies as Topic↗

PubMed1997

Optimizing collagen antigen unmasking in paraffin-embedded tissues.

In order to optimize collagen antigen unmasking in paraffin-embedded tissue sections, the effects of various fixatives and duration of fixation in relation to enzyme pretreatment and microwave irradiation for collagen antigen unmasking were studied. A streptavidin-biotin-peroxidase complex method was used for the immunolocalization of type III and IV collagen antigens. Fixatives and fixation time had significant adverse effects on the immunoreactivity of the antigens. Enzyme pretreatment was found to be superior to microwave irradiation for collagen antigen unmasking. Fixation with paraformaldehyde required shorter enzyme pretreatment and yielded a more enhanced reaction than treatment with formalin and Bouin's fluid. The optimum conditions for type III and IV collagen unmasking were found to be fixation with 4% paraformaldehyde in 0.01 M phosphate-buffered saline, pH 7.4, for up to 3 weeks followed by enzyme pretreatment with 1 mg ml-1 pepsin in 0.01 N hydrochloric acid, pH 2.0, for 30 min (human tissues) or 60 min (rat tissues) at 37 degrees C. It is concluded that collagen antigen unmasking by enzyme pretreatment in tissue sections fixed for a long period of time can be successful if appropriate enzyme(s) and incubation time(s) are employed with regard to the antigen under study and fixative and fixation time used for tissue preparation.

Animals↗

PubMed1997

Immunohistochemical detection of nucleolar protein p120 in paraffin-embedded tissues.

The monoclonal antibody FB-2 recognizes the antigen p120-kDa protein (p120), associated with the nucleolar matrix. p120 has originally been reported as expressed and detectable in malignant and non-neoplastic proliferating cells, but not in most normal resting tissues and benign tumours. In the present study, a reliable immunostaining method was used to detect p120 on formalin-fixed, paraffin wax-embedded tissue, testing it on 148 samples from different neoplastic and non-neoplastic tissues from different organs (breast, colon, lung, prostate, bladder, lymph nodes, skin, tongue and liver). The immunostaining was performed after the application of a specific antigen-unmasking protocol based on six consecutive cycles of microwave oven heating. Under these retrieval conditions, p120 antigen was clearly detectable, not only in hyperplastic and malignant cells, but also in stromal and normal non-proliferating cells of all the tissues evaluated. Our results show that the nucleolar protein p120 can be detected by routine immunohistochemistry in formalin-fixed, paraffin-embedded tissue and is expressed in all nucleated cells under any biological condition.

Antigens, Neoplasm↗

PubMed2000

Optimization of immunohistochemical methods using two different antigen retrieval methods on formalin-fixed paraffin-embedded tissues: experience with 63 markers.

Formalin fixation produces cross-links between the proteins and the fixative that alter the ability of some antibodies to recognize antigens. We used formalin-fixed, paraffin-embedded tissues to compare two different antigen retrieval methods for 63 antibodies used in the diagnosis of infectious and neoplastic diseases of animal species. Eighty-four percent of the antibodies needed some type of antigen retrieval for optimal results. Of those antibodies, 67.7% were monoclonal and 32.3% were polyclonal. Steam heat was the method of choice for 31 antibodies. Ten antibodies reacted only with steam heat, but 9 antibodies did not react when steam heat was used. Optimal results were obtained with enzyme digestion for 22 antibodies. Only 10 antibodies yielded optimal results without antigen retrieval; 64% of these antibodies were polyclonal. All antibodies against cytokeratins were optimally retrieved with proteinese K. Antigen retrieval appears to be necessary for the majority of antibodies when used with formalin-fixed, paraffin-embedded tissues.

Animal Diseases↗