A novel immunohistochemical staining method allows ultrarapid detection of lymph node micrometastases while conserving antibody

Rapid multiplex immunohistochemistry for characterizing tumor-immune microenvironment

Intratumoral immune profiles are related to prognosis and therapeutic efficacy, and could result in personalized treatments based on biomarkers. To develop a multiplex, quantitative, and rapid tissue evaluation method based on the clinically established standard immunohistochemistry (IHC), a 6-marker rapid multiplex IHC was developed based on our previously reported 14-marker multiplex IHC by reducing the number of labels and accelerating the staining procedure. First, fewer labels were required to identify the same immunological features linked to prognosis in 14-marker multiplex IHC analyses. The six selected markers showed a significant correlation with the 14 markers in the immune classification. Next, a rapid staining protocol was developed by optimizing the reaction temperature, chromogen, and washing time, allowing the completion of 6-marker analysis in 5 h and 49 min, as opposed to the several days required for conventional multiplex IHC. Validation of benign tonsil and head and neck cancer tissues revealed a significant correlation between rapid and conventional 6-makrer multiplex IHC in terms of staining intensities, densities of T cells, macrophages, lymphoid/myeloid immune cell ratios, and spatial profiles of intratumoral immune infiltrates. This method may enable quantitative assessment of the tumor-immune microenvironment on a clinically feasible time scale, which promotes the development of tissue biomarker-guided therapeutic strategies.

Intraoperative rapid immunohistochemistry with noncontact antibody mixing for undiagnosed pulmonary tumors

Knowledge of the histologic type and primary origin of pulmonary tumors is essential when preparing a surgical strategy. Intraoperative diagnosis of hematoxylin and eosin (H&E)-stained frozen sections is the gold standard, but reliable pathology requires time-consuming immunohistochemistry (IHC) to distinguish among histological types/organ origins and to analyze molecular status. The aim of this study was to evaluate the clinical reliability of a new rapid-IHC technique for intraoperative diagnosis of pulmonary tumors. In total, 169 patients with undiagnosed pulmonary tumors were enrolled in a multicenter prospective observational study. At three institutes, pulmonary tumor samples were collected through core needle biopsy and/or surgery to determine surgical strategies. Using a new device for rapid IHC, we applied a high-voltage, low-frequency alternating current (AC) field, which mixes the available antibody as the voltage is switched on/off. Rapid IHC can provide tumor histologic type/origin diagnoses within 20 min, as opposed to the 3-6 h required for conventional IHC. No false diagnoses of malignancy were rendered in any of the cases when using simple H&E staining. With H&E staining alone, the overall definitive diagnosis rate, the rate of defined tumor origin, and the rate of determined histological type were 76.92%, 85.80%, and 90.53%, respectively. When rapid IHC was added, those rates were significantly improved to 88.76%, 94.67%, and 91.72%, respectively. By providing prompt and accurate intraoperative histological/molecular analysis, rapid IHC driven by AC mixing could serve as an effective clinical tool guiding the surgical strategy for undiagnosed pulmonary tumors.

Rapid intraoperative Ki-67 immunohistochemistry for lung cancer using non-contact alternating current electric field mixing

OBJECTIVES

Locoregional recurrence of non-small cell lung cancer (NSCLC) occurs even among patients with stage I disease, as a result of tumor proliferative activity. The aim of this study was to evaluate the clinical reliability of a new rapid immunohistochemistry (IHC) technique for assessing malignant potential through detection of tumoral Ki-67 expression.

MATERIALS AND METHODS

The rapid IHC method uses non-contact alternating current (AC) mixing to achieve more rapid/stable staining within 20 min during surgery. First, to investigate the association between clinical outcomes and tumoral Ki-67 labeling with rapid IHC, 21 pairs of surgical patients treated between 2012 and 2020 for pStage IA1-3 NSCLC with/without recurrence were retrospectively reviewed. Second, 40 frozen section (FS) samples in patients with NSCLC for whom radical surgery was planned between April 2021 and February 2022 were deemed eligible for comparison of the clinical performance of conventional IHC and intraoperative rapid Ki-67 IHC with FS.

RESULTS

Detection of tumoral Ki-67 expression using rapid IHC with formalin-fixed, paraffin-embedded (FFPE) blocks was significantly associated with clinical outcomes in R0 pStage IA NSCLC surgical patients, including overall and recurrence-free survival (P = 0.0043 and P < 0.0001, respectively). Levels of Ki-67 expression among resectable NSCLC patients detected using rapid IHC with FS significantly correlated with those detected using conventional FFPE-IHC (p < 0.001). An intraoperative cut-off of > 7.5 % tumor cell Ki-67 positivity accurately predicted pathological stage more advanced than IA3 [P = 0.0185, Odds ratio = 20.477, 95 % confidence interval (CI): 1.660-252.55].

CONCLUSION

Rapid Ki-67 IHC with AC mixing could potentially serve as a clinical tool for intraoperative determination of tumor malignancy status. The present study suggests that segmentectomy for early small NSCLCs is oncologically safe and a reasonable alternative to lobectomy, but only when there is adequate intraoperative selection for primary tumors with low-grade malignancy, which could be verified using intraoperative rapid Ki-67 IHC with FS.

Novel rapid immunohistochemistry using an alternating current electric field identifies Rac and Cdc42 activation in human colon cancer FFPE tissues

It is important to determine the activation status of Rac and Cdc42 in cancer tissues for the prediction of metastasis and patient prognosis. However, it has been impossible to detect their spatial activation on formalin-fixed paraffin embedded (FFPE) surgical specimens thus far. Here, we established a novel detection technique for activated Rac/Cdc42 in human colon cancer FFPE tissues by using a p21-activated kinase (PAK)-Rac binding domain (RBD) detection probe fused with glutathione S-transferase (GST), designated GST-PAK-RBD, and novel rapid-immunohistochemistry (R-IHC) systems using noncontact alterating-current electric field mixing, although there is a technical limitation in that it may not distinguish between Rac members and Cdc42. In 50 cases of colon cancer, various activation patterns of Rac/Cdc42 were observed, which were designated plasma membrane, cytoplasm, mixed pattern, and polarized distribution. The activity was striking in the invasive fronts of tumors and significantly correlated with tumor invasion properties evaluated by TNM classification. Of note, in tissue microarray (TMA) samples, 29 of 33 cases demonstrated higher Rac1/Cdc42 activity in the tumor area than the corresponding normal mucosa. In addition, positive correlations were detected between Rac/Cdc42 activity and clinicopathological factors such as venous and lymphatic vessel invasion. These results suggest that understanding Rac and Cdc42 activations in cancer tissues would be valuable as an option for molecular therapy as personalized medicine.

Stapler-lavage cytology using a new rapid immunocytochemistry for evaluating surgical margin status after pulmonary sublobar resection

OBJECTIVE

Sublobar resection is considered the gold standard for selected patients with pulmonary metastasis or who are compromised in some way. However, an unfavorable outcome after sublobar resection is local/margin recurrence. The aim of this study was to evaluate the clinical reliability of a new rapid-stapler lavage immunocytochemistry (ICC) technique for assessing margin malignancy. The method uses non-contact alternating current (AC) mixing to achieve more stable staining.

METHODS

Twenty-one patients who underwent sublobar resection, including 16 wedge resections, for pulmonary metastasis or lung cancer in a compromised host between September 2016 and December 2017 were retrospectively reviewed. All margin specimens were intraoperatively evaluated with HE staining of frozen sections and stapler lavage cytology using Papanicolaou staining and rapid-ICC.

RESULTS

Rapid-stapler lavage ICC can be used to diagnose surgically safe margins within 20 min during sublobar resections. Although in all cases margins were diagnosed as cancer free based on HE staining of frozen sections, two of four patients diagnosed with malignant-positive margins based on rapid ICC experienced local/margin recurrence.

CONCLUSIONS

Rapid-stapler lavage ICC with AC mixing could potentially serve as a clinical tool for prompt determination of margin malignant status after pulmonary sublobar resection.

Harmonization across programmed death ligand 1 (PD-L1) assays for lung cancer by immunohistochemistry using noncontact alternating current electric field mixing

BACKGROUND

Immune checkpoint inhibitors (ICIs) are a promising advance in the treatment of patients with lung cancer. However, each ICI has been tested with an independently designed companion diagnostic assay that is based on a unique antibody. Consequently, the different trial-validated programmed death ligand 1 (PD-L1) immunohistochemistry (IHC) assays should not be considered interchangeable. Our aim was to compare the performance of each available PD-L1 antibody for its ability to accurately measure PD-L1 expression and to investigate the possibility of harmonization across antibodies through the use of a new rapid IHC system, which uses noncontact alternating current (AC) mixing to achieve more stable staining.

METHODS

First, 58 resected non-small cell lung cancer (NSCLC) specimens were stained using three PD-L1 IHC assays (28-8, SP142, and SP263) to assess the harmonization achieved with AC mixing IHC. Second, specimens from 27 patients receiving ICIs for postoperative recurrent NSCLC were stained using the same IHC method to compare the clinical performance of ICIs to PD-L1 scores. All patients received a tumor proportion score (TPS) with the 22C3 companion diagnostic test.

RESULTS

Better staining was achieved with the new AC mixing IHC method than the conventional IHC in PD-L1-positive cases, and the interchangeability of some combinations of assays was increased in PD-L1-positive. In addition, AC mixing IHC provided more appropriate overall response rates for ICIs in all assays.

CONCLUSIONS

Stable PD-L1 IHC driven by AC mixing helped to improve TPS scoring and patient selection for ICIs through interchangeable assays.

Rapid HER2 cytologic fluorescence in situ hybridization for breast cancer using noncontact alternating current electric field mixing

BACKGROUND

Human epidermal growth factor receptor 2-in situ hybridization (HER2-ISH) is widely approved for diagnostic, prognostic biomarker testing of formalin-fixed paraffin-embedded tissue blocks. However, cytologic ISH analysis has a potential advantage in tumor samples such as pleural effusion and ascites that are difficult to obtain the histological specimens. Our aim was to evaluate the clinical reliability of a novel rapid cytologic HER2 fluorescence ISH protocol (rapid-CytoFISH).

MATERIALS AND METHODS

Using a new device, we applied a high-voltage/frequency, noncontact alternating current electric field to tissue imprints and needle rinses, which mixed the probe within microdroplets as the voltage was switched on and off (AC mixing). Cytologic samples (n = 143) were collected from patients with immunohistochemically identified HER2 breast cancers. The specimens were then tested using standard dual-color ISH using formalin-fixed paraffin-embedded tissue (FFPE-tissue DISH) for HER2-targeted therapies, CytoFISH, and rapid-CytoFISH (completed within 4 h).

RESULTS

All 143 collected cytologic specimens (50 imprinted cytology specimens from resected tumors and 93 liquid-based cytology specimens from needle rinses) were suitable for FISH analysis. The HER2/chromosome enumeration probe (CEP) 17 ratios did not significantly differ between FFPE-tissue DISH and either CytoFISH protocol. Based on HER2 scoring criteria, we found 95.1% agreement between FFPE-tissue DISH and CytoFISH (Cohen's kappa coefficient = 0.771 and 95% confidence interval (CI): 0.614-0.927).

CONCLUSION

CytoFISH could potentially serve as a clinical tool for prompt determination of HER2 status in breast cancer cytology. Rapid-CytoFISH with AC mixing will enable cancer diagnoses and HER2 status to be determined on the same day a patient comes to a clinic or hospital.

Intraoperative diagnosis of lymph node metastasis during segmentectomy for non-small cell lung cancer by rapid immunohistochemistry using noncontact alternating current electric field mixing

Background

Although lobectomy is considered the standard surgery for any non‐small cell lung cancer (NSCLC), recent evidence indicates that for early NSCLCs segmentectomy may be equally effective. For segmentectomy to be oncologically safe, however, adequate intraoperative lymph node staging is essential. The aim of this study was to compare the results of a new rapid‐IHC system to the HE analysis for intraoperative nodal diagnosis in lung cancer patients considered for segmentectomy.

Methods

This retrospective study analyzed the pathological reports from NSCLC resections over a six‐year period between 2014 and 2020. Using a new device for rapid‐IHC, we applied a high‐voltage, low‐frequency alternating current (AC) field, which mixes the antipancytokeratin antibody as the voltage is switched on/off. Rapid‐IHC can provide a nodal diagnosis within 20 minutes.

Results

Frozen sections from 106 resected lymph nodes from 70 patients were intraoperatively evaluated for metastasis. Of those, five nodes were deemed positive based on both HE staining and rapid‐IHC. In addition, rapid‐IHC alone detected isolated tumor cells in one hilar lymph node. Three cStage IA patients with nodal metastasis detected with HE staining and rapid‐IHC received complete lobectomies. Five‐year relapse‐free survival and overall survival among patients receiving segmentectomy with rapid‐IHC were 88.77% and 88.79%, respectively.

Conclusions

Rapid‐IHC driven by AC mixing is simple, highly accurate, and preserves nodal tissue for subsequent tests. This system can be used effectively for intraoperative nodal diagnosis.

Rapid immunohistochemistry based on alternating‐current field mixing (completed within 20 minutes) is simple and highly accurate. This system will assist clinicians when making intraoperative diagnoses of lymph node metastasis and deciding upon the appropriate surgical procedure in segmentectomy for lung cancer.

Key points

Significant findings of the study

Rapid immunohistochemistry driven by alternating‐current field mixing (completed within 20 minutes intraoperatively) is simple, highly accurate, and preserves lymph node tissue for subsequent pathological examination, including molecular assessments.

What this study adds

Segmentectomy for lung cancer is oncologically safe, but only when there is adequate intraoperative node staging. Rapid immunohistochemistry will assist clinicians when making intraoperative nodal diagnoses.

Development of a Novel One-Step Automated Rapid in situ Hybridization for Anaplastic Lymphoma Kinase Rearrangement Using Non-Contact Alternating-Current Electric-Field Mixing

Echinoderm microtubule-associated protein-like 4 and anaplastic lymphoma kinase (ALK) fusion gene rearrangement is a key driver mutation in non-small cell lung cancer (NSCLC). Although Break-Apart ALK fluorescence in situ hybridization (FISH) is a reliable diagnostic method for detecting ALK gene rearrangement, it is also costly and time-consuming to use as a routine screening test. Our aim was to evaluate the clinical utility of a novel one-step, automated, rapid FISH (Auto-RaFISH) method developed to facilitate hybridization. This method takes advantage of the non-contact mixing effect of an alternating-current electric field. Ten representative specimens from 85 patients diagnosed at multiple centers with primary lung cancer with identified ALK-FISH status were collected. The specimens were all tested using FISH, RaFISH, and Auto-RaFISH. With both RaFISH protocols, the ALK test was completed within 4.5 h, as compared to the 20 h needed for the standard protocol. We found 100% agreement between the standard FISH, RaFISH, and new Auto-RaFISH based on the ALK status, and all methods stained equally well. These findings suggest that Auto-RaFISH could potentially serve as an automated clinical tool for prompt determination of ALK status in NSCLC.

Practical application of non-contact alternating current electric field mixing for reagent-saving in situ hybridisation of HER2

AIMS

Human epidermal growth factor receptor 2 (HER2)-targeted agents are effective against HER2-positive breast cancers. However, their lack of survival benefit in HER2-negative patients as well as their toxic effects and high cost highlight the need for accurate assessment of HER2 status. Our aim was to evaluate the clinical utility of a reagent-saving in situ hybridisation (Saving ISH) that facilitates hybridisation and saves HER2/chromosome enumeration probe by taking advantage of the non-contact mixing effect of an alternating current (AC) electric field.

METHODS

With a new device, we apply a high-voltage, low-frequency AC electric field to the tissue sections, which mixes the probe within microdroplets as the voltage is switched on and off. Specimens (n=113) from patients with breast cancers identified immunohistochemically as HER2 0/1(+), (2+) or (3+) were used. The specimens were all tested using conventional dual ISH (DISH), DISH with an automated slide stainer (ASS) and Saving ISH (1:1-1:3 dilution).

RESULTS

The Saving ISH with 1:2 probe dilution produced stable results with less non-specific staining while using smaller amounts of probe. The accuracy of HER2 status with Saving ISH was equal to standard. We found 96.4% agreement between DISH using ASS and Saving ISH (kappa coefficient=0.912).

CONCLUSIONS

These results suggest reagent-saving HER2 ISH could be used as a clinical tool for accurate and stable HER2 assessment, even when reagent concentrations vary.

Magnetically Promoted Rapid Immunofluorescence Staining for Frozen Tissue Sections

Current immunohistochemistry methods for diagnosing abnormal cells, such as cancer cells, require multiple steps and can be relatively slow compared with intraoperative frozen hematoxylin and eosin staining, and are therefore rarely used for intraoperative examination. Thus, there is a need for novel rapid detection methods. We previously demonstrated that functionalized fluorescent ferrite beads (FF beads) magnetically promoted rapid immunoreactions. The aim of this study was to improve the magnetically promoted rapid immunoreaction method using antibody-coated FF beads and a magnet subjected to a magnetic field. Using frozen sections of xenograft samples of A431 human epidermoid cancer cells that express high levels of epidermal growth factor receptor (EGFR) and anti-EGFR antibody-coated FF beads, we reduced the magnetically promoted immunohistochemistry procedure to a 1-min reaction and 1-min wash. We also determined the optimum magnetic force for the antibody reaction (from 7.79 × 10^-15 N to 3.35 × 10^-15 N) and washing (4.78 × 10^-16 N), which are important steps in this technique. Furthermore, we stained paraffin-embedded tissue arrays and frozen sections of metastatic breast cancer lymph nodes with anti-pan-cytokeratin antibody-coated FF beads to validate the utility of this system in clinical specimens. Under optimal conditions, this ultra-rapid immunostaining method may provide an ancillary method for pathological diagnosis during surgery. (J Histochem Cytochem 58:XXX-XXX, 2010).

Ultra-fast and automated immunohistofluorescent multistaining using a microfluidic tissue processor

Multistaining of a tissue section targeting multiple markers allows to reveal complex interplays in a tumor environment. However, the resource-intensive and impractically long nature of iterative multiplexed immunostainings prohibits its practical implementation in daily routine, even when using work-flow automation systems. Here, we report a fully automated and ultra-fast multistaining using a microfluidic tissue processor (MTP) in as short as 20 minutes per marker, by immunofluorescent staining employing commercially available tyramide signal amplification polymer precipitation by horse-radish peroxidase (HRP) activation. The reported duration includes (i) 15 minutes for the entire fluidic exchange and reagent incubation necessary for the immunostaining and (ii) 5 minutes for the heat-induced removal of the applied antibodies. Using the automated MTP, we demonstrated a 4-plex automated multistaining with clinically relevant biomarkers within 84 minutes, showing perfect agreement with the state-of-the-art microwave treatment antibody removal. The presented HRP-based method is in principle extendable to multistaining by both tyramides accommodating higher number of fluorescent channels and multi-color chromogenic staining. We anticipate that our automated multi-staining with a turn-around time shorter than existing monoplex immunohistochemistry methods has the potential to enable multistaining in routine without disturbing the current laboratory workflow, opening perspectives for implementation of -omics approaches in tissue diagnostics.

Reagent-saving immunohistochemistry for HER2 using non-contact alternating current electric field mixing

Aims

Human epidermal growth factor receptor 2 (HER2)-targeted agents are an effective approach to treating patients with HER2-positive breast cancer. However, the lack of survival benefit in HER2-negative patients, as well as the toxic effects and high cost of the drugs, highlight the need for accurate and prompt assessment of HER2 status. Our aim was to evaluate the clinical utility of a novel reagent-saving immunohistochemistry method (AC-IHC) that saves HER2 antibody by taking advantage of the non-contact mixing effect in microdroplets subjected to an alternating current electric field.

Methods

Ninety-five specimens were used from patients diagnosed with primary breast cancers identified immunohistochemically as HER2 0/1+, 2+ or 3+ using ASCO/CAP guideline-certified standard IHC. The specimens were all tested using the conventional IHC method (1:50 antibody dilution) as well as AC-IHC (1:50 dilution) and reagent-saving AC-IHC (1:100 dilution).

Results

The reagent-saving AC-IHC produced stable results with less non-specific staining using smaller amounts of labelled antibody. Moreover, the staining and accuracy of HER2 status evaluated with the reagent-saving AC-IHC method was equal to that achieved with standard IHC.

Conclusions

These results suggest reagent-saving AC-IHC could be used as a clinical tool for accurate and stable HER2 IHC, even when reagent concentrations vary.

Novel method for rapid fluorescence in-situ hybridization of ALK rearrangement using non-contact alternating current electric field mixing

Echinoderm microtubule-associated protein-like 4 gene and anaplastic lymphoma kinase gene (EML4-ALK) rearrangement is a key driver mutation in non-small cell lung cancer (NSCLC). Although Break-Apart ALK fluorescence in situ hybridization (FISH) is a reliable diagnostic method for detecting ALK gene rearrangement, it is too costly and time-consuming for use as a routine screening test. Our aim was to evaluate the clinical utility of a novel rapid FISH (RaFISH) method developed to facilitate hybridization. RaFISH takes advantage of the non-contact mixing effect of an alternating current (AC) electric field. Eighty-five specimens were used from patients diagnosed with NSCLC identified immunohistochemically as ALK 0, (1/2+) or (3+). With RaFISH, the ALK test was completed within 4.5 h, as compared to 20 h needed for the standard FISH. Although RaFISH produced results more promptly, the staining and accuracy of the ALK evaluation with RaFISH was equal to the standard. We found 97.6% agreement between FISH and RaFISH based on the status of the ALK signals. These results suggest RaFISH could be used as a clinical tool to promptly determine ALK status.

CD147 expression correlates with lymph node metastasis in T1-T2 squamous cell carcinoma of the tongue

Cervical lymph node metastasis causes a poor prognosis in cases of stage T1-T2 squamous cell carcinoma (SCC) of the tongue. Recent studies have reported that cluster of differentiation (CD)147, also known as extracellular matrix metalloproteinase inducer, contributes to tumor progression. The present study evaluated the role of CD147 in the tumorigenesis of SCC of the tongue in vitro, as well as the association between CD147 expression and cervical lymph node metastasis in clinical samples of SCC of the tongue. Tongue SCC cell lines were used to evaluate in vitro tumorigenesis. In addition, 41 patients with clinical stage T1-T2 tongue SCC were assessed with a histopathological analysis. Univariate and multivariate analysis were performed to investigate the risk of cervical lymph node metastasis associated with histopathological findings. In the in vitro study, cell invasiveness was upregulated by S100 calcium-binding protein A9 (S100A9) stimulation and downregulated following CD147-blocking antibody treatment. The univariate and multivariate analyses identified CD147 expression in the invasive tumor front as an independent risk factor for metastasis. It was concluded that CD147 induces tongue carcinoma cell invasion through its interaction with S100A9. Thus, an evaluation of the extent of CD147 expression in cancer cell nests at the invasive tumor front may help in predicting cervical lymph node metastasis in patients with clinical N0 T1-T2 tongue SCC.

Microfluidics for rapid cytokeratin immunohistochemical staining in frozen sections

Frozen sections (FS) of tumor samples represent a cornerstone of pathological intraoperative consultation and have an important role in the microscopic analysis of specimens during surgery. So far, immunohistochemical (IHC) stainings on FS have been demonstrated for a few markers using manual methods. Microfluidic technologies have proven to bring substantial improvement in many fields of diagnostics, though only a few microfluidic devices have been designed to improve the performance of IHC assays. In this work, we show optimization of a complete pan-cytokeratin chromogenic immunostaining protocol on FS using a microfluidic tissue processor into a protocol taking <12 min. Our results showed specificity and low levels of background. The dimensions of the microfluidic prototype device are compatible with the space constraints of an intraoperative pathology laboratory. We therefore anticipate that the adoption of microfluidic technologies in the field of surgical pathology can significantly improve the way FSs influence surgical procedures.

Novel rapid-immunohistochemistry using an alternating current electric field for intraoperative diagnosis of sentinel lymph nodes in breast cancer

Axillary lymph node status and pathological diagnosis of sentinel lymph nodes (SLNs) is a prognostic factor that influences management of postoperative therapy. Recent reports indicate that one-step nucleic acid amplification and hematoxylin and eosin (HE)-stained frozen sections are effective for intraoperative diagnosis of SLNs. In the present study, we report a rapid-immunohistochemical staining (R-IHC) method that enables intraoperative detection of SLN metastases within 16 min using an anti-cytokeratin antibody. This is the first report on SLN diagnosis using R-IHC in patients with breast cancer. We prospectively examined 160 dissected SLNs from 108 breast cancer patients who underwent surgery at our institute. The dissected SLNs were sectioned and conventionally stained with HE or immunohistochemically labeled with anti-cytokeratin antibody using R-IHC procedures. Intraoperative R-IHC analyses were completed within 16 min, after which diagnoses were made by two pathologists. The total time required for intraoperative diagnosis was about 20 min. In this study series, R-IHC detected four metastatic SLNs that were undetected using conventional HE staining (4/20, 20.0%). Compared with subsequent permanent diagnosis, R-IHC offered 95.2% sensitivity and 100% specificity. These findings indicate R-IHC is a clinically applicable technique that enables precise and quick intraoperative detection of micro- and macrometastasis in breast cancer.

Rapid Immunohistochemistry With Thyroid Transcription Factor-1 for Pulmonary Adenocarcinoma

BACKGROUND

Intraoperative pathologic diagnosis of solitary pulmonary tumors to differentiate between metastatic and primary lung cancer is extremely important to determine the appropriate range of excision. Accurate intraoperative pathologic evaluation may be often difficult, however, and needs additional immunohistochemical (IHC) evaluation to support the diagnosis. Although conventional IHC is a powerful tool for diagnosis, its clinical use is limited intraoperatively because of time constraints. To address this issue, we developed a device that enables complete and rapid IHC (R-IHC) analyses within 20 minutes. We aimed to evaluate the discriminative ability of the R-IHC with anti-thyroid transcription factor-1 (TTF-1) antibody, which is a highly specific IHC marker for primary lung adenocarcinoma.

METHODS

A total of 61 pulmonary tumors that were resected at our institute from May 2011 to September 2013 were retrospectively examined. The samples were sectioned, labeled with anti-TTF-1 antibody using the R-IHC method, and pathologically evaluated. The standard used for evaluation was conventional IHC with TTF-1.

RESULTS

With the R-IHC procedure, analyses were completed within 20 minutes, with a diagnostic accuracy of 96.7% (59 of 61). Among the 47 primary lung adenocarcinomas, the R-IHC detected 31 (66%) tumors that were positive for TTF-1, with a positive predictive value of 100% (31 of 31).

CONCLUSIONS

Our newly developed method of R-IHC with anti-TTF-1 antibody was useful for diagnosing and differentiation of solitary pulmonary tumors. This technology may prove to be an important supplement to standard intraoperative pathologic diagnosis in routine practice.

Novel method for rapid in-situ hybridization of HER2 using non-contact alternating-current electric-field mixing

Human epidermal growth factor receptor 2 (HER2)-targeted agents are an effective approach to treating HER2-positive breast cancer patients. However, the lack of survival benefit in HER2-negative patients as well as the toxic effects and high cost of the drugs highlight the need for accurate and prompt assessment of HER2 status. Our aim was to evaluate the clinical utility of a novel rapid dual in-situ hybridization (RISH) method developed to facilitate hybridization. The method takes advantage of the non-contact mixing effect of an alternating current (AC) electric field. One hundred sixty-three specimens were used from patients diagnosed with primary breast cancers identified immunohistochemically as HER2 0/1(+), (2+) or (3+). The specimens were all tested using conventional dual in-situ hybridization (DISH), DISH with an automated slide stainer, and RISH. With RISH the HER2 test was completed within 6 h, as compared to 20–22 h needed for the standard protocol. Although RISH produced results more promptly using smaller amounts of labeled antibody, the staining and accuracy of HER2 status evaluation with RISH was equal to or greater than with DISH. These results suggest RISH could be used as a clinical tool to promptly determine HER2 status.

Rapid immunocytochemistry based on alternating current electric field using squash smear preparation of central nervous system tumors

The role of intraoperative pathological diagnosis for central nervous system (CNS) tumors is crucial for neurosurgery when determining the surgical procedure. Especially, treatment of carmustine (BCNU) wafers requires a conclusive diagnosis of high-grade glioma proven by intraoperative diagnosis. Recently, we demonstrated the usefulness of rapid immunohistochemistry (R-IHC) that facilitates antigen-antibody reaction under alternative current (AC) electric field in the intraoperative diagnosis of CNS tumors; however, a higher proportion of water and lipid in the brain parenchyma sometimes leads to freezing artifacts, resulting in poor quality of frozen sections. On the other hand, squash smear preparation of CNS tumors for cytology does not affect the frozen artifacts, and the importance of smear preparation is now being re-recognized as being better than that of the tissue sections. In this study, we established the rapid immunocytochemistry (R-ICC) protocol for squash smears of CNS tumors using AC electric field that takes only 22 min, and demonstrated its usefulness for semi-quantitative Ki-67/MIB-1 labeling index and CD 20 by R-ICC for intraoperative diagnosis. R-ICC by AC electric field may become a substantial tool for compensating R-IHC and will be applied for broad antibodies in the future.

Novel method for immunofluorescence staining of mammalian eggs using non-contact alternating-current electric-field mixing of microdroplets

Recently, a new technique was developed for non-catalytically mixing microdroplets. In this method, an alternating-current (AC) electric field is used to promote the antigen–antibody reaction within the microdroplet. Previously, this technique has only been applied to histological examinations of flat structures, such as surgical specimens. In this study, we applied this technique for the first time to immunofluorescence staining of three-dimensional structures, specifically, mammalian eggs. We diluted an antibody against microtubules from 1:1,000 to 1:16,000, and compared the chromatic degree and extent of fading across dilutions. In addition, we varied the frequency of AC electric-field mixing from 5 Hz to 46 Hz and evaluated the effect on microtubule staining. Microtubules were more strongly stained after AC electric-field mixing for only 5 minutes, even when the concentration of primary antibody was 10 times lower than in conventional methods. AC electric-field mixing also alleviated microtubule fading. At all frequencies tested, AC electric-field mixing resulted in stronger microtubule staining than in controls. There was no clear difference in a microtubule staining between frequencies. These results suggest that the novel method could reduce antibody consumption and shorten immunofluorescence staining time.

Development of a New Magnetometer for Sentinel Lymph Node Mapping Designed for Video-Assisted Thoracic Surgery in Non-Small Cell Lung Cancer

BACKGROUND

We previously developed a method for sentinel lymph node (SLN) mapping in non-small cell lung cancer (NSCLC), based on the magnetic force produced by a magnetite tracer already approved for use as a contrast material for magnetic resonance imaging. However, it is difficult to use that technique with video-assisted thoracic surgery (VATS) because the sensing element of the magnetometer is large and thick. The purpose of the present study was to develop a smaller, thinner VATS-compatible magnetometer.

METHODS

The tracer employed was Ferucarbotran, a colloidal solution of superparamagnetic iron oxide coated with carbodextran. Fifteen patients with clinical stage I NSCLC were enrolled, and each received 1.6 mL of Ferucarbotran, injected intraoperatively at 5 points around the tumor. The magnetic force within the sampling lymph nodes was measured using the new VATS-compatible magnetometer.

RESULTS

SLNs were detected in 11 (73.3%) of the 15 patients using the VATS-compatible magnetometer. The average number of SLNs identified per patient was 1.8 (range 0-4). No complications related to the SLN detection method were observed.

CONCLUSIONS

The new VATS-compatible magnetometer appears to have substantial advantages over techniques using a radioisotope and our earlier magnetometer, as it can be inserted through the small VATS port site.