A rapid immunostaining method for frozen sections

Rapid Immunohistochemistry Based on Ultrasonic Thermal Steam Heating for Improvement of Intraoperative Diagnosis

OBJECTIVES

To evaluate the role of rapid immunohistochemistry (RIHC) based on ultrasonic thermal steam heating in improving diagnostic accuracy of intraoperative frozen section diagnosis and to recommend RIHC antibody panels for pathologic differential diagnosis.

MATERIALS AND METHODS

RIHC based on ultrasonic thermal steam heating was tested for intraoperative frozen diagnosis with difficulty in diagnosis, and all slides were reviewed and compared with the final diagnosis. Ninety-three cases of surgical specimens involving RIHC examination were studied. Discordance rates with paraffin immunohistochemistry were calculated.

RESULTS

In 93 cases where RIHC was performed, 85 cases (91%) were proven to be helpful for the diagnosis. A total of 58 antibodies were used for RIHC 276 times, of which 19 antibodies were not effective 25 times. Fifteen RIHC antibody panels are recommended based on staining stability and utilization frequency.

CONCLUSION

After improving the staining method, ultrasonic thermal steam heating RIHC is practical, convenient, and cost-effective, making it suitable for use in any pathology department with routine immunohistochemistry reagents. It plays an important auxiliary role in improving the accuracy of intraoperative rapid pathologic diagnosis.

THE EFFECTS OF ETANERCEPT AND CABERGOLINE ON ENDOMETRIOTIC IMPLANTS, UTERUS AND OVARIES IN RAT ENDOMETRIOSIS MODEL

The pathophysiology of endometriosis is still unknown and treatment options remain controversial. Searches focus on angiogenesis, stem cells, immunologic and inflammatory factors. This study investigated the effects of etanercept and cabergoline on ovaries, ectopic, and eutopic endometrium in an endometriosis rat model. This randomized, placebo-controlled, blinded study included 50 rats, Co(control), Sh(Sham), Cb(cabergoline), E(etanercept), and E + Cb(etanercept + cabergoline) groups. After surgical induction of endometriosis, 2^nd operation was performed for endometriotic volume and AMH level. After 15 days of treatment: AMH level, flow cytometry, implant volume, histologic scores, immunohistochemical staining of ectopic, eutopic endometrium, and ovary were evaluated at 3^rd operation. All groups had significantly reduced volume, TNF-α, VEGF, and CD 146/PDGF-Rβ staining of endometriotic implants comparing to the Sh group (p < 0.05).TNF-α staining of eutopic endometrium in all treatment groups was similar to Sh and Co groups (p > 0.05). E and E + Cb groups significantly decreased TNF-α staining in the ovary comparing to Sh, Co, and Cb groups (p < 0.05). All treatment groups had significantly higher AFC compared to the Sh group. CD25⁺ Cells' median percentage was significantly increased in the E + Cb group compared to Co, Sh, Cb, and E group. E + Cb group had a significantly higher CD5⁺ Cells' level than the Co group (p = 0.035). In conclusion; Etanercept and/or Cabergoline decreased volume, TNF-α, VEGF, and CD 146/PDGF-Rβ staining of the ectopic endometrial implant. E and E + Cb treatment decreased TNF-α levels in the ovary. E + Cb also increased peripheral blood CD25⁺ & CD5⁺ Cell's.

Exploiting altered patterns of choline kinase-alpha expression on human prostate tissue to prognosticate prostate cancer

AIMS

Malignant transformation results in overexpression of choline-kinase (CHK) and altered choline metabolism, which is potentially detectable by immunohistochemistry (IHC). We investigated the utility of CHK-alpha (CHKA) IHC as a complement to current diagnostic investigation of prostate cancer by analysing expression patterns in normal (no evidence of malignancy) and malignant human prostate tissue samples.

METHODS

As an initial validation, paraffin-embedded prostatectomy specimen blocks with both normal and malignant prostate tissue were analysed for CHKA protein and mRNA expression by western blot and quantitative reverse transcriptase PCR (qRT-PCR), respectively. Subsequently, 100 paraffin-embedded malignant prostate tumour and 25 normal prostate cores were stained for both Ki67 (labelling-index: LI) and CHKA expression.

RESULTS

The validity of CHKA-antibody was verified using CHKA-transfected cells and siRNA knockdown. Immunoblotting of tissues showed good resolution of CHKA protein in malignant prostate, verifying use of the antibody for IHC. There was minimal qRT-PCR detectable CHKA mRNA in normal tissue, and conversely high expression in malignant prostate tissues. IHC of normal prostate cores showed mild (intensity) CHKA expression in only 28% (7/25) of samples with no Ki67 expression. In contrast, CHKA was expressed in all malignant prostate cores along with characteristically low proliferation (median 2% Ki67-LI; range 1-17%). Stratification of survival according to CHK intensity showed a trend towards lower progression-free survival with CHK score of 3.

CONCLUSIONS

Increased expression of CHKA, detectable by IHC, is seen in malignant lesions. This relatively simple cost-effective technique (IHC) could complement current diagnostic procedures for prostate cancer and, therefore, warrants further investigation.

Quantitative measurement of cancer tissue biomarkers in the lab and in the clinic

Detection of biomolecules in tissues provides contextual information and the possibility to assess the interaction of different cell types and markers. Routine qualitative assessment of immune- and oligonucleotide-based methods in research and the clinic has been associated with assay variability because of lack of stringent validation and subjective interpretation of results. As a result, the vast majority of in situ assays in clinical usage are nonquantitative and, although useful, often of questionable scientific validity. Here, we revisit the reporters and methods used for single- and multiplexed in situ visualization of protein and RNA. Then we examine methods for the use of quantitative platforms for in situ measurement of protein and mRNA levels. Finally, we discuss the challenges of the transition of these methods to the clinic and their potential role as tools for development of companion diagnostic tests.

Comparative evaluation of an extensive histopathologic examination and a real-time reverse-transcription-polymerase chain reaction assay for mammaglobin and cytokeratin 19 on axillary sentinel lymph nodes of breast carcinoma patients

OBJECTIVE

To assess the accuracy of a commercially available real-time reverse-transcription-polymerase chain reaction assay for mammaglobin and cytokeratin 19 mRNAs [GeneSearch Breast Lymph Node (BLN) Assay, Veridex LLC, Warren, NJ] in the detection of axillary sentinel lymph nodes (SLNs) metastases in patients with breast carcinoma.

SUMMARY BACKGROUND DATA

Because of the lack of standardized and widely accepted protocols for a truly accurate histopathologic examination of SLN, the relative merits of alternative assays based on the identification of tumor specific mRNA markers deserve further assessment.

METHODS

: A prospective series of 293 consecutive SLNs from 293 patients was evaluated. The BLN assay results were compared with those of an extensive histopathologic examination of the entire SLNs performed on serial frozen sections cut at 40 to 50 microm intervals.

RESULTS

The BLN assay correctly identified 51 of 52 macrometastatic and 5 of 20 micrometastatic SLNs, with a sensitivity of 98.1% to detect metastases larger than 2 mm, 94.7% for metastases larger than 1 mm, and 77.8% for metastases larger than 0.2 mm. The overall concordance with histopathology was 90.8%, with specificity of 95.0%, positive predictive value of 83.6%, and negative predictive value of 92.9%. When the results were evaluated according to the occurrence of additional metastases to non-SLN in patients with histologically positive SLNs, the assay was positive in 33 (91.7%) of the 36 patients with additional metastases and in 22 (66.6%) of the 33 patients without further echelon involvement.

CONCLUSIONS

The sensitivity of the reverse-transcription -polymerase chain reaction assay is comparable to that of the histopathologic examination of the entire SLN by serial sectioning at 1.5 to 2 mm.

Freshly prepared immune complexes with intermittent microwave irradiation result in rapid and high-quality immunostaining

We have previously reported that intermittent microwave irradiation shortened the primary or secondary antibody incubation time to 10 min in a special moist chamber. To achieve precise immunostaining within 1h, we attempted to generate a novel procedure, "freshly prepared immune complex with intermittent microwave irradiation (f-IC-M)". The advantage of this immunostaining procedure lies in a one-step incubation instead of primary and then secondary antibody application. In this study, we employed five primary antibodies to examine the efficiency and quality of this procedure. As expected, every primary antibody examined brought about precise immunostaining within 45 min for formalin-fixed, paraffin-embedded sections, and within 15 min for frozen sections. In addition, this procedure is able to generate double-immunoenzymatic staining with different enzyme-labeled primary antibodies if desired. As any combination of primary and secondary antibodies is possible by this one-step application, f-IC-M increases the efficiency of immunostaining without losing quality. Therefore, this procedure is able to rapidly provide diagnostic information to the pathologists.

Microwave-assisted antigen retrieval and incubation with cox-2 antibody of archival paraffin-embedded human oligodendroglioma and astrocytomas

Immunohistochemistry is an important tool that is often used for the diagnosis of pathologies; however, the length of time required to process the tissue is relatively long. Furthermore, the quality and sensitivity of immunohistochemical staining is affected by formalin fixation which results in variable loss of antigenicity, known as masking effect. Here we assess the effect of microwave irradiation on the incubation time required to obtain high quality immunohistochemical staining for cox-2 using archival formalin-fixed, paraffin-embedded human oligodendrogliomas and astrocytomas. The results show that intermittent microwave irradiation during the incubation with the primary antibody reduced the time requirement to 5 min while the staining quality was indistinguishable from 1 or 24 h long incubations. Thus, the use of this procedure results in a significant saving of time which is important for a timely diagnosis of pathological conditions that await treatment.

Dextramers: New generation of fluorescent MHC class I/peptide multimers for visualization of antigen-specific CD8+ T cells

Direct identification as well as isolation of antigen-specific T cells became possible since the development of "tetramers" based on avidin-fluorochrome conjugates associated with mono-biotinylated class I MHC-peptide monomeric complexes. In principle, a series of distinct class I MHC-peptide tetramers, each labelled with a different fluorochrome, would allow to simultaneously enumerate as many unique antigen-specific CD8(+) T cells. Practically, however, only phycoerythrin and allophycocyanin conjugated tetramers have been generally available, imposing serious constraints for multiple labeling. To overcome this limitation, we have developed dextramers which are multimers based on a dextran backbone bearing multiple fluorescein and streptavidin moieties. Here we demonstrate the functionality and optimization of these new probes on human CD8(+) T cell clones with four independent antigen specificities. Their applications to the analysis of relatively low frequency antigen-specific T cells in peripheral blood, as well as their use in fluorescence microscopy, are demonstrated. The data show that dextramers produce a stronger signal than their fluoresceinated tetramer counterparts. Thus, these could become the reagents of choice as the antigen-specific T cell labeling transitions from basic research to clinical application.

Rapid Intraoperative Immunohistochemical Evaluation of Sentinel Lymph Nodes for Metastatic Breast Carcinoma

OBJECTIVE

Sentinel lymph node (SLN) biopsy is an integral part of the surgical management of patients with breast cancer. Rapid immunohistochemistry (RIHC) has the potential to increase detection of metastatic carcinoma at the time of frozen section consultation. The authors assessed the accuracy and turnaround time of a newly developed RIHC method for pancytokeratin (RIHC-CK).

METHODS

Sixty-six SLNs from 32 patients with breast carcinoma were examined for metastasis using the Zymed Sentinel Lymph Node Rapid IHC Kit. Intraoperative frozen sections (6 mum) of the SLNs were incubated with Zymed anti-pan-cytokeratin/HRP conjugate, diaminobenzidine (DAB), and stained with hematoxylin. Slides were ready within 8 minutes and were interpreted as positive or negative for metastatic carcinoma. Results were compared with previous intraoperative touch preparations, frozen sections, hematoxylin and eosin (Perm H&E), and AEl/3-immunostained permanent sections (Perm CK).

RESULTS

Fourteen lymph nodes (19%) in 13 patients tested positive for metastatic carcinoma in Perm H&E, the gold standard. RIHC-CK had the highest sensitivity (92%) of the intraoperative tests, compared with touch preparations (64%) and frozen sections (80%). RIHC-CK showed 94% accuracy, compared with 96% (frozen section) and 93% (touch preparation). The RIHC technique took 8 minutes and was easy to perform and interpret.

CONCLUSIONS

Zymed RIHC is a sensitive method for detecting breast cancer metastases in SLNs. The speed, accuracy, and ease of interpretation of the test allow for recognition of micrometastases (<2 mm) that might otherwise be undetectable by current methods of intraoperative evaluation. The prognostic significance and effect on surgical management of micrometastases in SLNs have yet to be determined.

Pathologic examination of the axillary sentinel lymph nodes in patients with early-stage breast carcinoma: current and resolving controversies on the basis of the European Institute of Oncology experience

Several controversial aspects of sentinel lymph node biopsy (SLNB) for patients with early-stage, node-negative breast carcinoma have been dealt with and resolved in the past decade since its introduction. Unfortunately, however, there is still no consensus on how best to examine sentinel lymph nodes (SLN) histologically. As a consequence, the protocols for SLN examination are remarkably variable in different institutions, leading to a very poor reproducibility of the data stemming from investigations on series of patients whose SLNs have been evaluated according to diverse protocols. Patient outcomes, however, can be optimised only by standardization of the whole procedure of SLNB, with particular reference to the histopathologic scrutiny. Lack of a standardized histopathologic protocol likely derives also from the uncertainties about the clinical implications of minimal lymph node involvement (isolated tumour cells and micrometastases) with regard both to the risk of additional metastases to non-sentinel lymph nodes of the same basin and to the prognostic value for patients' survival. This review aims at highlighting some of the controversial issues of the histopathologic examination of the SLNs, including the number of sections and cutting intervals, the use of immunohistochemistry and the role of molecular biology assays.

Improved 1-h rapid immunostaining method using intermittent microwave irradiation: practicability based on 5 years application in Toyama Medical and Pharmaceutical University Hospital

Immunostaining depending on antigen-antibody specificity is the commonest approach for determining the localization of specific antigens in tissue sections. This procedure is applicable not only with frozen or specially fixed samples, but also has proved reliable with formalin-fixed paraffin-embedded tissue sections through improvement of antigen-retrieval. Immunostaining is thus firmly established as a tool for diagnostic pathology and in our institute multiple antibodies are applied for 13-15% of the cases examined, as well as H and E staining. With the standard approach, approximately 3 h is necessary from the beginning of deparaffinization till covering sections with the Envision system. We utilized intermittent microwave irradiation for 10 min during hybridization with primary and secondary antibodies in a special moist-chamber, to achieve all immunostaining steps within 1 h in 178 primary antibodies frequently used for diagnostic pathology. According to our 5 years experience, such microwave irradiation not only obtained significant specific staining for enhancing the specificity of antigen-antibody reactions, but also inhibited nonspecific binding. We present herein the details of the methodology and recommendations for its application with particular primary antibodies. This method can contribute to savings in time and energy, allowing pathologists to rapidly obtain diagnostic information.

Comparison of contrast, sensitivity and efficiency of signal amplified and nonamplified immunohistochemical reactions suitable for videomicroscopy-based quantification and neuroimaging

In recent years, many different technical modifications of immunohistochemical methods have been developed. The selection of a suitable technique for quantitative purposes such as mapping studies can be quite difficult. Various features of a certain method must be considered such as the sensitivity, costs, duration and practicability with respect to serial sectioned specimens. Background and foreground difference or contrast and the influence of artifacts are major problems of quantitative immunohistochemistry. It is not known which of the different modifications of immunohistochemical signal amplifications and non-amplifications gives optimal results in respect to image analytical-based quantification. However, for image analysis, it is important to analyze sections which offer a sufficient contrast between foreground and background. The sensitivity of a system is crucial when quantitative immunohistochemistry should be applied to scarce material with longer postmortem and storage times which occur often by processing human brains. In addition, the enzyme-substrate reactions have an obvious influence on this criterion; therefore, different substrates were also tested. The contrast may be as well effected by the quality and specificity of the primary antibody, the type of tissue and naturally by preparative (fixation, postmortem delay, storage) and individual factors (age, circadian effects, diseases, sex). Because all of these factors may yield to different results by combining them with different neuronal structures, we used three different antigen expressions for a specific analysis: fibrillary, granulary and perikaryal antigen distributions in brains from Wistar rats. Principally, the sensitivity of the modifications of immunohistochemical amplifications is revealed more strongly than without enhancement steps; however, the contrast between foreground and background structures does not necessary increase by applying a certain amplification technique. The lowest contrast (15%) was detected after applying the labelled streptavidin-biotin technique. All other methods offer comparable contrasts in between 30% and 40%. The catalyzed signal amplification reaction has been found to give optimal results (40% contrast) for image analysis. However, from the technical point of view and variability of protein expression, storage and postmortem delay, it was necessary to adapt the commercial CSA Kit from Dako (K1500). The modified technique, called C2 method, offers better results with respect to sensitivity, total costs, duration and contrast (60%) and variability of contrast.

Histopathologic examination of axillary sentinel lymph nodes in breast carcinoma patients

The axillary sentinel lymph node biopsy (SLNB) has gained increasing popularity as a novel surgical approach for staging patients with breast carcinoma and for guiding the choice of adjuvant therapy with minimal morbidity. Patients with negative SLNB represent a subset of breast carcinoma patients with definitely better prognosis, because their pN0 status is based on a very thorough examination of the sentinel lymph nodes (SLNs), with a very low risk of missing even small micrometastatic deposits, as compared with routine examination of the 20 or 30 lymph nodes obtained by the traditional axillary clearing. The histopathologic examination of the SLNs may be performed after fixation and embedding in paraffin, or intraoperatively on frozen sections. Whatever is the preferred tracing technique and surgical procedure, the histopathologic examination of each SLN must be particularly accurate, to avoid a false-negative diagnosis. Unfortunately, because of the lack of standardised guidelines or protocols for SLN examination, different institutions still adopt their own working protocols, which differ substantially in the number of sections cut and examined, in the cutting intervals (ranging from 50 to more than 250 microm), and in the more or less extensive use of immunohistochemical assays for the detection of micrometastatic disease. Herein, a very stringent protocol for the examination of the axillary SLN is reported, which is applied either to frozen SLN for the intraoperative diagnosis, and to fixed and embedded SLN as well.

Intraoperative imprint cytologic evaluation of sentinel lymph nodes for lobular carcinoma of the breast

BACKGROUND

The evaluation of sentinel lymph nodes (SLNs) from a woman with lobular cancer of the breast is frequently challenging. Intraoperative imprint cytology (IIC) is equivalent to frozen sectioning for rapid SLN evaluation and is advantageous because it is rapid, reliable, cost-effective, and conserves tissue. Metastatic lobular carcinoma is difficult to identify in SLN because of its low-grade cytomorphology, its tendency to infiltrate lymph nodes in a single cell pattern, and because individual cells can resemble lymphocytes. We are unaware of any large published studies, using any technique, to evaluate SLN for lobular carcinoma.

METHODS

A retrospective review of the intraoperative imprint cytology results of 678 SLN mapping procedures for breast carcinoma was performed. From this cohort, we studied SLN from cases of lobular carcinoma. These SLN were evaluated intraoperatively by either bisecting or slicing the SLN into 4-mm sections. Imprints were made of each cut surface and stained with hematoxylin and eosin and/or Diff-Quik. Permanent sections were evaluated with up to 4 hematoxylin and eosin-stained levels and cytokeratin immunohistochemistry. IIC results were compared with final histologic results.

RESULTS

Sixty-one cases of pure invasive lobular carcinoma were identified. Sensitivity was 52%, specificity was 100%, accuracy was 82%, negative predictive value was 78%. No statistically significant differences in sensitivity, specificity or accuracy were identified for the intraoperative detection of lobular carcinoma versus ductal carcinoma. The sensitivity for detecting macrometastases (more than 2 mm) was better than for detecting micrometastases, 73 versus 25%, respectively (P = 0.059).

CONCLUSIONS

The sensitivity and specificity of IIC are similar to that of intraoperative frozen section evaluation. Therefore, IIC is a viable alternative to frozen sectioning when intraoperative evaluation is required. If SLN micrometastasis is used to determine the need for further lymphadenectomy, more sensitive intraoperative methods will be needed to avoid a second operation.

Application of immunofluorescence for intraoperative evaluation of sentinel lymph nodes in patients with breast carcinoma

BACKGROUND

Sentinel lymph node (SLN) sampling is used to predict axillary lymph node (AxLN) metastasis in patients with breast carcinoma; AxLN sampling can be avoided in SLN-negative patients. Multistep sectioning and immunohistochemistry are reported to increase the sensitivity of micrometastasis detection. The authors used immunofluorescence (IF) staining with cytokeratin (CK) antibodies for intraoperative evaluation of touch imprints from multistep sections of SLNs.

METHODS

A combined total of 150 SLNs from 69 patients who had breast carcinoma and underwent surgery were analyzed. SLNs were sectioned at 2 mm intervals, and touch imprints subsequently were prepared. After ethanol fixation, slides were incubated with fluorescein isothiocyanate-conjugated CK and propidium iodide and then subjected to microwave irradiation for 3 minutes. Finally, fluorescence microscopy was used to evaluate slides for the presence or absence of metastatic disease.

RESULTS

Metastatic disease was identified in 36 (24.0%), 26 (17.3%), 32 (21.3%), and 31 (20.7%) of 150 lymph nodes using IF staining, Papanicolaou (Pap) staining, immunocytochemical (ICC) staining, and hematoxylin and eosin (H and E) staining, respectively. The sensitivities of IF, Pap, ICC, and H and E staining were 94.6%, 70.3%, 86.5%, and 83.8%, respectively. Except for IF staining (specificity, 99.1%), each method had a specificity of 100%. The accuracy rates for IF, Pap, ICC, and H and E staining were 98.0%, 92.7%, 96.7%, and 96.0%, respectively.

CONCLUSIONS

IF is a rapid, highly sensitive, and highly specific staining technique by which touch imprints can be used to intraoperatively evaluate SLNs in patients with breast carcinoma.

Corneal changes in magnesium-deficient rats

PURPOSE

The purpose of the current study is to investigate the cornea in magnesium (Mg) deficiency and elucidate the local function of trace elements.

METHODS

After delivery, mother Wistar Kyoto rats were fed a low Mg diet containing 0.1 mg Mg/100 g diet with all other nutrients and distilled and deionized water. Infant rats were suckled by their mothers for 21 days and then fed the same Mg-deficient diet. Control mother rats were fed commercial rat pellets containing 24 mg Mg/100 g diet and all other nutrients. The corneas were examined by electron microscopy at 6 weeks of age.

RESULTS

In the Mg-deficient rats, serum Mg levels were significantly lower and calcium (Ca) levels higher than in the control rats. The corneas of Mg-deficient rats showed decreased microvilli and microplicae in the epithelial cells of the most superficial layer, increased mitochondria with abnormal shapes in the basal cells in the epithelium, condensed chromatin in the nuclei of the basal cells, and high density deposits and macrophage-like cells in the subepithelium of the stroma. Mg-deficient rats had pentagonal and square endothelial cells.

CONCLUSION

Since Mg2+ has biologic functions including structural stabilization of protein, nucleic acids, and cell membranes, Mg deficiency may induce changes in the corneal surface and nuclei of corneal epithelial and endothelial cells. These disturbances may interfere with protection from infections, foreign bodies, dryness, and direct exposure to air. Thus, Mg is essential for the cornea to maintain normal structure and function.

Rapid immunohistochemistry for cytokeratin in the intraoperative evaluation of sentinel lymph nodes for metastatic breast carcinoma

The sensitivity and specificity of detecting metastatic breast carcinoma in sentinel lymph nodes using a rapid immunohistochemistry technique was determined and compared with methods currently used at the authors' institution. At the time of intraoperative consultation, after routine diagnostic touch preparations and frozen sections were prepared, 6-microm frozen sections of 72 sentinel lymph nodes from 32 patients with breast carcinoma were placed on plus slides, fixed in cold acetone for 2 or 3 minutes, and stored at -70 degrees C. These sections were immunostained with a prediluted broad-spectrum anticytokeratin monoclonal antibody coupled to an inert polymer with horseradish peroxidase (DAKO EPOS). Slides were ready for interpretation within 16 minutes and were scored as positive, negative, or equivocal for metastatic carcinoma. Results were compared with those of the intraoperative touch preparations and frozen sections and with paraffin-embedded, hematoxylin and eosin-stained, and AE1/AE3 immunostained permanent sections. Fourteen (19%) sentinel lymph nodes were positive for metastatic carcinoma in 13 patients. All methods tested were 100% specific. The rapid immunohistochemistry method was the least sensitive (57% sensitivity) of all methods used to detect metastasis. Routine diagnostic touch preparations, frozen sections, and permanent sections had sensitivities of 69%, 86%, and 100% respectively. In conclusion, this rapid immunohistochemistry method would not be helpful in intraoperative assessment of sentinel lymph nodes in breast cancer patients due to its low sensitivity.

Intraoperative evaluation of axillary sentinel lymph nodes using touch imprint cytology and immunohistochemistry: I. Protocol of rapid immunostaining of touch imprints

AIMS

Sentinel Node Biopsy (SNB) is considered an accurate method of detecting axillary lymph node status in patients with small breast cancer. Combined with an accurate and rapid histopathology tool, it could spare this group of patients unnecessary Axillary Node Clearance (ANC) with its associated hazards. Intraoperative examination of SNB for cancer cells has been investigated using both Frozen Sections (FS) and Imprint Cytology (IC) stained with different stains. This study is devoted to establish a reliable and rapid protocol for immunostaining of touch imprints from SNB.

METHODS

We investigated two different EPOS (Enhanced Polymer One-Step staining--DAKO) anticytokeratin antibodies, five different tissue fixatives and different incubation periods and temperatures with both positive and negative controls.

RESULTS

We have developed a protocol, which produced good and consistent immunostaining of touch imprints. The initial results using this protocol are concordant with those of permanent Haematoxylin and Eosin (H&E) sections.

CONCLUSIONS

We propose this protocol for rapid immunostaining of touch imprints of SNB.

The problem of the accuracy of intraoperative examination of axillary sentinel nodes in breast cancer

BACKGROUND

Sentinel node (SN) biopsy has become accepted as a reliable method of predicting the state of the axilla in breast cancer. The key issue, however, is the accuracy of the pathological evaluation of the biopsied node, which should be done intraoperatively whenever possible.

METHODS

In our initial experience on 192 patients using a conventional intraoperative frozen section method, the false-negative rate was 6.3%, and the negative predictive value was 93.7%. We devised a new and exhaustive intraoperative method, requiring about 40 minutes, in which pairs of sections are taken every 50 microm for the first 15 sections and every 100 microm thereafter, sampling the entire node. Sentinel node metastases were found in 143 of the 376 T1N0 cases examined (38%).

RESULTS

Metastases were always identified on hematoxylin and eosin sections, although in 4% of cases, cytokeratin immunostaining on adjacent sections was useful for confirming malignancy. In 233 patients the SNs were disease-free; of these patients, 222 had metastasis-free axillary nodes, and 11 (4.7%) had another metastatic node.

CONCLUSION

Extensive intraoperative examination of frozen sentinel nodes correctly predicts an uninvolved axilla in 95.3% of cases (negative predictive value). This method is, therefore, suitable for identifying patients in whom axillary dissection can be avoided.

A new rapid immunohistochemical staining technique using the EnVision antibody complex

Rapid immunohistochemical investigation, in addition to staining with hematoxylin and eosin, would be useful during intraoperative frozen section diagnosis in some cases. This study was undertaken to investigate whether the recently described EnVision system, a highly sensitive two-step immunohistochemical technique, could be modified for rapid immunostaining of frozen sections. Forty-five primary antibodies were tested on frozen sections from various different tissues. After fixation in acetone for 1 min and air-drying, the sections were incubated for 3 min each with the primary antibody, the EnVision complex (a large number of secondary antibodies and horseradish peroxidase coupled to a dextran backbone), and the chromogen (3,3'diaminobenzidine or 3-amino-9-ethylcarbazole). All reactions were carried out at 37C. Specific staining was seen with 38 antibodies (including HMB-45 and antibodies against keratin, vimentin, leukocyte common antigen, smooth muscle actin, synaptophysin, CD34, CD3, CD20, and prostate-specific antigen). A modification of the EnVision method allows the detection of a broad spectrum of antigens in frozen sections in less than 13 min. This method could be a useful new tool in frozen section diagnosis and research. (J Histochem Cytochem 49:623-630, 2001)

Amplification methods for the immunolocalization of rare molecules in cells and tissues

The needs to precisely assign macromolecules to specific locations and domains within tissues and cells and to reveal antigens which are present in low or even in trace amounts, led to the elaboration of a wide spectrum of immunocytochemical amplification procedures. These arise from the successive improvements of tissue preparation techniques, of antigen retrieval procedures and of immunological or non-immunological detection systems. Improvement of detection systems may be the most active in the development of amplification techniques. Since the early work of Coons, in which by the introduction of the indirect technique has started amplifying the signal, different systems have succeeded in increasing the sensitivity of antigens detection. Indeed, amplification techniques such as the multiple antibody layers, the multiple bridges, the enzyme complexes, the avidin-biotin, the silver intensification, and the numerous variations and combinations among these have increased the sensitivity for the detection of scarce tissue antigens. However, as shown by the recent progress carried out with new approaches such as the catalyzed reporter deposition (CARD) and the enhanced polymer one-step staining (EPOS), more efficient methods are still needed. In electron microscopy, few techniques have reached the resolution afforded by the post-embedding immunogold approach. In spite of this and in order to further increase its sensitivity, new probes and novel approaches are allowing combination of the gold marker with the amplification capacity of enzymes afforded by the CARD technique. Immunogold amplification strategies, such as the multiple incubations with the primary antibody and the use of an anti-protein A antibody have also led to enhanced signals displaying the advantages in terms of resolution and possibilities of quantification inherent to the colloidal gold marker.

The application of direct immunofluorescence to intraoperative neurosurgical diagnosis

A diagnostic problem can occur at the time of intraoperative consultation of neurosurgical tumors as to whether the tumor is of neuroectodermal origin or whether it represents an epithelial metastasis from another site. Intraoperative diagnoses based on hematoxylin and eosin stained frozen sections are often later confirmed by immunocytochemical analysis of formalin-fixed, paraffin-embedded tissue sections that are not available at the time of surgery. The objective of the current study was to demonstrate that the application of direct immunofluorescence to the intraoperative diagnosis of neurosurgical tumors would provide unequivocal, and nearly immediate results. This report describes a new application of an existing technique for an optimized, rapid procedure utilizing direct immunocytochemistry with fluorescence-labeled primary antibodies to analyze surgical biopsies intraoperatively. The examination of five neurosurgical biopsies established a neuroectodermal origin of three tumors via immunolabeling for glial fibrillary acidic protein (GFAP) and lack of labeling with keratin markers, whereas several metastatic lung carcinomas were identified by immunostaining for keratin, but not GFAP, markers. The results of the direct immunolabeling method were unequivocal and required only minutes. The same diagnoses were confirmed by standard immunocytochemical labeling of formalin-fixed, paraffin-embedded sections, though it required several days to obtain the results. Direct immunofluorescence using fluorescently conjugated primary antibodies is a practical and rapid method for deciding whether a neurosurgical tumor is a primary glial or an epithelial metastatic tumor in origin. It is the first reported application of the technique for this aspect of rapid neurosurgical diagnosis.

A novel immunohistochemical detection system using mirror image complementary antibodies (MICA)

AIMS

To describe and illustrate a novel and highly sensitive peroxidase-based immunohistochemical detection system which employs mutually attractive, mirror image complementary antibodies (MICA).

METHODS AND RESULTS

To demonstrate the sensitivity of the MICA system alongside the avidin-biotin complex (ABC) method, we selected a range of mouse monoclonal and rabbit polyclonal primary antibodies against antigens that are generally regarded as relatively difficult or impossible to detect on formalin-fixed, paraffin-embedded lymphoid tissue. Compared with the ABC method, the MICA immunodetection method enabled us to dilute primary antibodies up to 200-fold with equivalent or superior immunostaining results and, usually, considerably shortened primary antibody incubation times.

CONCLUSIONS

We have described and illustrated a novel immunohistochemical detection system and demonstrated greatly increased sensitivity over the commonly used ABC system. An additional advantage of the MICA system is that it is avidin-free and so avoids non-specific staining due to endogenous tissue biotin.

Protocol for ultrarapid immunostaining of frozen sections

Rapid immunostaining of frozen sections within a tolerable time span would be very helpful for intraoperative diagnosis. A protocol was therefore established using the enhanced polymer one-step staining (EPOS) system (Dako) with antibodies against leucocyte common antigen (LCA), cytokeratin (CK), and anti-melanoma (MEL). Best results with reliable and specific immunostaining and a labelling intensity comparable to standard immunostaining protocols were achieved with fixation of samples in 100% acetone for 20 seconds (CK, LCA) or two minutes (MEL), followed by incubation of the primary antibody and development of the chromogen reaction with 3,3'diaminobenzidine (DAB) for three and five minutes at 37 degrees C, respectively. The total procedure takes only 12 minutes, thus enabling rapid immunostaining on intraoperative frozen sections. Apart from its use in tumour classification, this method is especially useful in detecting tumour cells in sentinel lymph nodes.

Sentinel lymphadenectomy in breast cancer: identification of sentinel lymph node and detection of metastases

Sentinel lymphadenectomy is a useful way of assessing axillary status and obviating axillary dissection in patients with node-negative breast cancer. However, controversies remain concerning the optimal method to identify the sentinel lymph node (SLN) and detect micrometastases in this lymph node. We reviewed the literature concerning sentinel lymphadenectomy in breast cancer and reached the following conclusions: (a) A combination of preoperative lymphoscintigraphy with intraoperative dye-guided and gamma probe-guided methods achieves a higher rate of identification of SLN than any of these techniques alone. (b) Immediate and reliable intraoperative assessment of sentinel node status is vital to the technique's success. However, the reliability of sentinel node diagnosis using frozen sections is questionable, because micrometastatic foci cannot always be identified. (c) Hematoxylin and eosin (H&E) staining and/or immunohistochemistry on permanent sections are useful for the detection of micrometastases in the sentinel node. Although a reverse transcriptase-polymerase chain reaction (RT-PCR) method is more sensitive than H&E staining and immunohistochemistry, it would not distinguish benign from malignant epithelial cells in the SLN. Therefore, further study is required before sentinel lymphadenectomy gains general acceptance for patients with primary breast cancer.

The EnVision++ system: a new immunohistochemical method for diagnostics and research. Critical comparison with the APAAP, ChemMate, CSA, LABC, and SABC techniques

AIM

To assess a newly developed immunohistochemical detection system, the EnVision++.

METHODS

A large series of differently processed normal and pathological samples and 53 relevant monoclonal antibodies were chosen. A chessboard titration assay was used to compare the results provided by the EnVision++ system with those of the APAAP, CSA, LSAB, SABC, and ChemMate methods, when applied either manually or in a TechMate 500 immunostainer.

RESULTS

With the vast majority of the antibodies, EnVision++ allowed two- to fivefold higher dilutions than the APAAP, LSAB, SABC, and ChemMate techniques, the staining intensity and percentage of expected positive cells being the same. With some critical antibodies (such as the anti-CD5), it turned out to be superior in that it achieved consistently reproducible results with differently fixed or overfixed samples. Only the CSA method, which includes tyramide based enhancement, allowed the same dilutions as the EnVision++ system, and in one instance (with the anti-cyclin D1 antibody) represented the gold standard.

CONCLUSIONS

The EnVision++ is an easy to use system, which avoids the possibility of disturbing endogenous biotin and lowers the cost per test by increasing the dilutions of the primary antibodies. Being a two step procedure, it reduces both the assay time and the workload.

Sentinel Lymphadenectomy in Breast Cancer: An Alternative to Routine Axillary Dissection

We reviewed the literature concerning sentinel lymphadenectomy in breast cancer and reached the following conclusions: (a) A combination of lymphoscintigraphy and dye-guided and/or gamma probe-guided techniques are superior to either technique alone for identifying the sentinel lymph node. (b) lmmediate and reliable intraoperative information on the sentinel node is vital for the technique's success. However, the reliability of sentinel node diagnosis using frozen sections is questionable, because micrometastatic foci cannot be identified. (c) A reverse transcriptase-polymerase chain reaction(RT-PCR)method is more sensitive than immunohistochemistry for the detection of micrometastasis in the sentinel node. (d) Until there are new tumor markers or new imaging techniques to identify axillary metastasis without operative intervention, sentinel lymphadenectomy is a highly accurate, minimally invasive way to assess disease extent. Before sentinel lymphadenectomy gains general acceptance for patients with primary breast cancer, however, a large clinical trial will be essential to verify the value of this technology.

Sentinel-node biopsy to avoid axillary dissection in breast cancer with clinically negative lymph-nodes

BACKGROUND

Axillary lymph-node dissection is an important staging procedure in the surgical treatment of breast cancer. However, early diagnosis has led to increasing numbers of dissections in which axillary nodes are free of disease. This raises questions about the need for the procedure. We carried out a study to assess, first, whether a single axillary lymph node (sentinel node) initially receives malignant cells from a breast carcinoma and, second, whether a clear sentinel node reliably forecasts a disease-free axilla.

METHODS

In a consecutive series of 163 women with operable breast carcinoma, we injected microcolloidal particles of human serum albumin labelled with technetium-99m. This tracer was injected subdermally, close to the tumour site, on the day before surgery, and scintigraphic images of the axilla and breast were taken 10 min, 30 min, and 3 h later. A mark was placed on the skin over the site of the radioactive node (sentinel node). During breast surgery, a hand-held gamma-ray detector probe was used to locate the sentinel node, and make possible its separate removal via a small axillary incision. Complete axillary lymphadenectomy was then done. The sentinel node was tagged separately from other nodes. Permanent sections of all removed nodes were prepared for pathological examination.

FINDINGS

From the sentinel node, we could accurately predict axillary lymph-node status in 156 (97.5%) of the 160 patients in whom a sentinel node was identified, and in all cases (45 patients) with tumours less than 1.5 cm in diameter. In 32 (38%) of the 85 cases with metastatic axillary nodes, the only positive node was the sentinel node.

INTERPRETATION

In the large majority of patients with breast cancer, lymphoscintigraphy and gamma-probe-guided surgery can be used to locate the sentinel node in the axilla, and thereby provide important information about the status of axillary nodes. Patients without clinical involvement of the axilla should undergo sentinel-node biopsy routinely, and may be spared complete axillary dissection when the sentinel node is disease-free.

Our experience with the enhanced polymer one-step staining in frozen sections

The enhanced polymer one-step staining (EPOS) method is presented with minor modifications for intraoperative frozen sections. It can be applied in almost every department of pathology where there is a necessity, because no special equipment is required. The method is rapid and immunostaining can be performed in less than 15 min. Antibodies are available for more than 20 important tissue and tumor markers. Out of those, antibodies against human cytokeratin, leukocyte common antigen (LCA) and chromogranin A were introduced in routine work. The first 2 antibodies yield excellent results and are a big advantage in routine diagnostic work: the use of cytokeratin is useful for confirmation or exclusion of suspected tumor invasion, especially in cases of atypical hyperplastic lesions, for detection of spindle cell carcinomas, and the detection of lymph node micrometastases. LCA demonstration is helpful in differentiating various round cell tumors, such as poorly differentiated carcinomas, sarcomas, malignant lymphomas, and evaluation of inflammatory response. Chromogranin A may detect neuroendocrine differentiation in the tumors.