The Clinical Utility of a Tiered Approach to Pediatric Glioma Molecular Characterization for Resource-Limited Settings.

PURPOSE: Molecular characterization is key to optimally diagnose and manage cancer. The complexity and cost of routine genomic analysis have unfortunately limited its use and denied many patients access to precision medicine. A possible solution is to rationalize use-creating a tiered approach to testing which uses inexpensive techniques for most patients and limits expensive testing to patients with the highest needs. Here, we tested the utility of this approach to molecularly characterize pediatric glioma in a cost- and time-sensitive manner. METHODS: We used a tiered testing pipeline of immunohistochemistry (IHC), customized fusion panels or fluorescence in situ hybridization (FISH), and targeted RNA sequencing in pediatric gliomas. Two distinct diagnostic algorithms were used for low- and high-grade gliomas (LGGs and HGGs). The percentage of driver alterations identified, associated testing costs, and turnaround time (TAT) are reported. RESULTS: The tiered approach successfully characterized 96% (95 of 99) of gliomas. For 82 LGGs, IHC, targeted fusion panel or FISH, and targeted RNA sequencing solved 35% (29 of 82), 29% (24 of 82), and 30% (25 of 82) of cases, respectively. A total of 64% (53 of 82) of samples were characterized without targeted RNA sequencing. Of 17 HGG samples, 13 were characterized by IHC and four were characterized by targeted RNA sequencing. The average cost per sample was more affordable when using the tiered approach as compared with up-front targeted RNA sequencing in LGG ($405 US dollars [USD] v $745 USD) and HGGs ($282 USD v $745 USD). The average TAT per sample was also shorter using the tiered approach (10 days for LGG, 5 days for HGG v 14 days for targeted RNA sequencing). CONCLUSION: Our tiered approach molecularly characterized 96% of samples in a cost- and time-sensitive manner. Such an approach may be feasible in neuro-oncology centers worldwide, particularly in resource-limited settings.

Update on immunohistochemistry in bone and soft tissue tumors: Cost-effectively replacing molecular testing with immunohistochemistry.

Soft tissue tumors form part of a challenging domain in diagnostic pathology owing to their comparative rarity, astonishing histologic diversity, and overlap between entities. Many of these tumors are now known to be defined by highly recurrent, or, in some instances, unique molecular alterations. Insights from gene profiling continue to elucidate the wider molecular landscape of soft tissue tumors; many of these advances have been co-opted by immunohistochemistry (IHC) for diagnostic applications. There now exists a multitude of antibodies serving as surrogate markers of recurrent gene fusions, amplifications, and point mutations, which, in certain settings, can replace the need for more resource and time-intensive cytogenetic and molecular genetic analyses. IHC presents many advantages including rapid turnaround time, cost-effectiveness, and interpretative reproducibility. A sensible application of these immunohistochemical markers complemented by a working knowledge of the molecular pathogenesis of bone and soft tissue tumors permits accurate diagnosis in the majority of cases. In this review, we will outline some of these biomarkers while emphasizing molecular correlates and highlighting interpretative challenges and pitfalls.

Oncotype DX Predictive Nomogram for Recurrence Score Output: The Novel System ADAPTED01 Based on Quantitative Immunochemistry Analysis.

PURPOSE: Oncotype DX (ODX) predicts breast cancer recurrence risk, guiding the choice of adjuvant treatment. In many countries, access to the test is not always available. We used correlation between phenotypical tumor characteristics, quantitative classical immunohistochemistry (IHC), and recurrence score (RS) assessed by ODX to develop a decision supporting system for clinical use. PATIENTS AND METHODS: Breast cancer patients who underwent ODX testing between 2014 and 2018 were retrospectively included in the study. The data selected for analysis were age, menopausal status, and pathologic and IHC features. IHC was performed with standardized quantitative methods. The data set was split into two subsets: 70% for the training set and 30% for the internal validation set. Statistically significant features were included in logistic models to predict RS ≤ 25 or ≤ 20. Another set was used for external validation to test reproducibility of prediction models. RESULTS: The internal set included 407 patients. Mean (range) age was 53.7 (31-80) years, and 222 patients (54.55%) were > 50 years old. ODX results showed 67 patients (16.6%) had RS between 0 and 10, 272 patients between 11 and 25 (66.8%), and 68 patients > 26 (16.6%). Logistic regression analysis showed that RS score (for threshold ≤ 25) was significantly associated with estrogen receptor (P = .004), progesterone receptor (P < .0001), and Ki-67 (P < .0001). Generalized linear regression resulted in a model that had an area under the receiver operating characteristic curve (AUC) of 92.2 (sensitivity 84.2%, specificity 80.1%) and that was well calibrated. The external validation set (183 patients) analysis confirmed the model performance, with an AUC of 82.3 and a positive predictive value of 91%. A nomogram was generated for further prospective evaluation to predict RS ≤ 25. CONCLUSION: RS was related to quantitative IHC in patients with RS ≤ 25, with a good performance of the statistical model in both internal and external validation. A nomogram for enhancing clinical approach in a cost-effective manner was developed. Prospective studies must test this application in clinical practice.

Economic and feasibility comparison of the dRIT and DFA for decentralized rabies diagnosis in resource-limited settings: The use of Nigerian dog meat markets as a case study.

BACKGROUND: Rabies lyssavirus (RABV) is the aetiologic agent of rabies, a disease that is severely underreported in Nigeria as well as elsewhere in Africa and Asia. Despite the role that rabies diagnosis plays towards elucidating the true burden of the disease, Nigeria-a country of 180 million inhabitants-has a limited number of diagnostic facilities. In this study, we sought to investigate two of the World Organization for Animal Health (OIE)-recommended diagnostic assays for rabies-viz; the direct fluorescent antibody test (DFA) and the direct rapid immunohistochemical test (dRIT) in terms of their relative suitability in resource-limited settings. Our primary considerations were (1) the financial feasibility for implementation and (2) the diagnostic efficacy. As a case study, we used suspect rabies samples from dog meat markets in Nigeria. METHODS/PRINCIPAL FINDINGS: By developing a simple simulation framework, we suggested that the assay with the lowest cost to implement and routinely use was the dRIT assay. The costs associated with the dRIT were lower in all simulated scenarios, irrespective of the number of samples tested per year. In addition to the cost analysis, the diagnostic efficacies of the two assays were evaluated. To do this, a cohort of DFA-positive and -negative samples collected from dog meat markets in Nigeria were initially diagnosed using the DFA in Nigeria and subsequently sent to South Africa for diagnostic confirmation. In South Africa, all the specimens were re-tested with the DFA, the dRIT and a quantitative real-time polymerase chain reaction (qRT-PCR). In our investigation, discrepancies were observed between the three diagnostic assays; with the incongruent results being resolved by means of confirmatory testing using the heminested reverse transcription polymerase reaction and sequencing to confirm that they were not contamination. CONCLUSIONS/SIGNIFICANCE: The data obtained from this study suggested that the dRIT was not only an effective diagnostic assay that could be used to routinely diagnose rabies, but that the assay was also the most cost-effective option among all of the OIE recommended methods. In addition, the results of our investigation confirmed that some of the dogs slaughtered in dog markets were rabies-positive and that the markets posed a potential public health threat. Lastly, our data showed that the DFA, although regarded as the gold standard test for rabies, has some limitations-particularly at low antigen levels. Based on the results reported here and the current challenges faced in Nigeria, we believe that the dRIT assay would be the most suitable laboratory test for decentralized or confirmatory rabies diagnosis in Nigeria, given its relative speed, accuracy, cost and ease of use.

The predicted impact and cost-effectiveness of systematic testing of people with incident colorectal cancer for Lynch syndrome.

OBJECTIVES: To evaluate the health impact and cost-effectiveness of systematic testing for Lynch syndrome (LS) in people with incident colorectal cancer (CRC) in Australia. DESIGN, SETTING, PARTICIPANTS: We investigated the impact of LS testing strategies in a micro-simulation model (Policy1-Lynch), explicitly modelling the cost of testing all patients diagnosed with incident CRC during 2017, with detailed modelling of outcomes for patients identified as LS carriers (probands) and their at-risk relatives throughout their lifetimes. For people with confirmed LS, we modelled ongoing colonoscopic surveillance. MAIN OUTCOME MEASURES: Cost-effectiveness of six universal tumour testing strategies (testing for DNA mismatch repair deficiencies) and of universal germline gene panel testing of patients with incident CRC; impact on cost-effectiveness of restricting testing by age at CRC diagnosis (all ages, under 50/60/70 years) and of colonoscopic surveillance interval (one, two years). RESULTS: The cost-effectiveness ratio of universal tumour testing strategies (annual colonoscopic surveillance, no testing age limit) compared with no testing ranged from $28 915 to $31 904/life-year saved (LYS) (indicative willingness-to-pay threshold: $30 000-$50 000/LYS). These strategies could avert 184-189 CRC deaths with an additional 30 597-31 084 colonoscopies over the lifetimes of 1000 patients with incident CRC with LS and 1420 confirmed LS carrier relatives (164-166 additional colonoscopies/death averted). The most cost-effective strategy was immunohistochemistry and BRAF V600E testing (incremental cost-effectiveness ratio [ICER], $28 915/LYS). Universal germline gene panel testing was not cost-effective compared with universal tumour testing strategies (ICER, $2.4 million/LYS). Immunohistochemistry and BRAF V600E testing was cost-effective at all age limits when paired with 2-yearly colonoscopic surveillance (ICER, $11 525-$32 153/LYS), and required 4778-15 860 additional colonoscopies to avert 46-181 CRC deaths (88-103 additional colonoscopies/death averted). CONCLUSIONS: Universal tumour testing strategies for guiding germline genetic testing of people with incident CRC for LS in Australia are likely to be cost-effective compared with no testing. Universal germline gene panel testing would not currently be cost-effective.

Flex-Array® - a novel multi-well vessel system for the immobilization and multi-modal testing of intact formalin-fixed paraffin-embedded (FFPE) cells or tissues.

Flex-Array® is a novel multi-well system that extends the key features of current high-performance microscope slides used in advanced staining techniques. The Flex-Array® system facilitates the immobilization of FFPE cell or tissue sections onto a multi-well array for the subsequent performance of single analyte (IHC) or multiplexed immunohistochemistry (MIHC). Additionally, the Flex-Array® device is compatible with fluorescent and colorimetric in situ hybridization (FISH) and adds new capabilities such as replicate analysis, quantitative ELISA-like assays and microdissection-free nucleic acid extraction. The Flex-Array® facilitates rapid, contextually rich and high-precision multi-modal analysis of FFPE cells and tissues at a significant reduction in testing, data acquisition and analysis costs.

Comparison of different stains in exfoliated oral mucosal cell micronucleus of potentially malignant disorders of oral cavity.

BACKGROUND: Micronucleus (MN) has been proved to be an important biomarker of genomic damage. Leishman Giemsa (LG) cocktail, being a relatively new staining technique, has not been used in exfoliative cytology. The aim of this study is to observe and compare the micronuclei (MN) frequency in potentially malignant disorders (PMDs) and also to compare the staining efficacy of May-Grünwald Giemsa (MGG), LG cocktail, and Papanicolaou (PAP) for micronuclei in exfoliated oral mucosal cells. MATERIALS AND METHODS: Three smears were prepared from each 30 controls (buccal mucosa) and 120 patients (40 oral submucous fibrosis, 40 lichen planus, and 40 leukoplakia) clinically diagnosed with having one of the PMDs of the oral cavity stained with PAP, MGG, and LG cocktail stains. MN frequency (No. of MN/1000 cells) was evaluated and compared between the cases and the controls. Comparison between the three different stained smears was also made to determine the clarity and efficacy of the stains. RESULTS: LG cocktail gave comparatively better results followed by PAP and MGG. Statistically significant results (P < 0.05) were obtained, using Mann-Whitney test for comparison of MN frequency between cases and controls. CONCLUSION: LG cocktail is an easy, cost- effective, and one step technique comparable to PAP staining; however, it warrants further study in its potential application in screening of oral cancer.

Comparison of methodologies for the detection of BRAF mutations in bone marrow trephine specimens.

AIMS: BRAF V600E detection assists in the diagnosis of hairy cell leukaemia (HCL); however, testing practices vary. We evaluated the clinical utility of 5 BRAF mutation testing strategies for use on bone marrow trephines (BMT). METHODS: 11 HCL, 5 HCL 'mimic', 2 treated HCL and 10 normal BMT specimens were tested for mutant BRAF, comparing Sanger sequencing, pyrosequencing, amplicon-based next generation sequencing (NGS), automated (Idylla) PCR and immunohistochemistry (IHC). RESULTS: PCR and IHC were cheaper and identified V600E in 100 % of HCL cases. Pyrosequencing detected the mutation in 91%, NGS in 55% of cases and Sanger sequencing in 27%. All assays gave wild-type BRAF results in HCL mimics and normal BMT samples. CONCLUSIONS: PCR and IHC were most sensitive and cost-effective, but these have limited scope for multiplexing and are likely to be replaced by NGS gene panels or whole genome sequencing in the medium to long term.

What impacts the cost-effectiveness of PD-L1 testing in non-small cell lung cancer?

Programmed Death Ligand 1(PD-L1) testing is recommended for patients with Non-Small Cell Lung Cancer (NSCLC) at stage IIIB and IV, adenocarcinoma and squamous cell carcinoma. Up to now, no clinical-pathological parameters are perfectly able to select a positive PD-L1-patient. For this reason PD-L1 testing is mandatory for patients with advanced NSCLC for whom an immune checkpoint inhibitor treatment is appropriate. Several studies on the cost-effectiveness of immune checkpoint inhibitors in this subset of patients have been published. Chouaid et al. (Lung Cancer 127, 2019, 44-52) assessed the cost-effectiveness of pembrolizumab versus standard of care platinum-based chemotherapy from the French health care system perspective. The authors did not, however, mention that the type of PD-L1 testing used can impact the cost of therapy, which varies according to methods used and to the country where PD-L1 testing is performed. The lack of specific guidelines can lead to discrepancies in technical and/or clinical validation procedures of PD-L1 testing, and that this also impacts the cost of therapy. In conclusion, the effect of PD-L1 testing on cost-effectiveness of immune checkpoint inhibitors depends on the antibody and platform used for patient selection. The barriers to overcome are the limited quantity of biological material available and lack of standardization of the PD-L1 IHC test methods.

Balancing Adherence and Expense: The Cost-Effectiveness of Two-Sample vs One-Sample Fecal Immunochemical Test.

Colorectal cancer (CRC) causes more than 50,000 deaths each year in the United States but early detection through screening yields survival gains; those diagnosed with early stage disease have a 5-year survival greater than 90%, compared to 12% for those diagnosed with late stage disease. Using data from a large integrated health system, this study evaluates the cost-effectiveness of fecal immunochemical testing (FIT), a common CRC screening tool. A probabilistic decision-analytic model was used to examine the costs and outcomes of positive test results from a 1-FIT regimen compared with a 2-FIT regimen. The authors compared 5 diagnostic cutoffs of hemoglobin concentration for each test (for a total of 10 screening options). The principal outcome from the analysis was the cost per additional advanced neoplasia (AN) detected. The authors also estimated the number of cancers detected and life-years gained from detecting AN. The following costs were included: program management of the screening program, patient identification, FIT kits and their processing, and diagnostic colonoscopy following a positive FIT. Per-person costs ranged from $33 (1-FIT at 150ng/ml) to $92 (2-FIT at 50ng/ml) across screening options. Depending on willingness to pay, the 1-FIT 50 ng/ml and the 2-FIT 50 ng/ml are the dominant strategies with cost-effectiveness of $11,198 and $28,389, respectively, for an additional AN detected. The estimates of cancers avoided per 1000 screens ranged from 1.46 to 4.86, depending on the strategy and the assumptions of AN to cancer progression.

Low cost immunohistochemistry bench for developing countries.

No abstract available.

Barriers to Lynch Syndrome Testing and Preoperative Result Availability in Early-onset Colorectal Cancer: A National Physician Survey Study.

OBJECTIVE: Although widely recommended, Lynch syndrome (LS) testing with tumor microsatellite instability (MSI) and/or immunohistochemistry (IHC) is infrequently performed in early-onset colorectal cancer (CRC), and CRC generally. Reasons are poorly understood. Hence, we conducted a national survey focusing on gastroenterologists, as they are frequently first to diagnose CRC, assessing testing barriers and which specialist is felt responsible for ordering MSI/IHC. Additionally, we assessed factors influencing timing of MSI/IHC ordering; testing on colonoscopy biopsy, opposed to post-operative surgical specimens, assists decisions on preoperative germline genetic testing and extent of colonic resection (ECR). METHODS: A 21-question web-based survey was distributed through an American College of Gastroenterology email listing. RESULTS: In total 509 completed the survey. 442 confirmed gastroenterologists were analyzed. Only 33.4% felt gastroenterologists were responsible for MSI/IHC ordering; pathologists were believed most responsible (38.6%). Cost, unfamiliarity interpreting results and unavailable genetic counseling most commonly prevented routine ordering (33.3%, 29.2%, 24.9%, respectively). In multivariable analysis, non-academic and rural settings were associated with cost and genetic counseling barriers. Only 46.1% felt MSI/IHC should always be performed on colonoscopy biopsy. Guideline familiarity predicted whether respondents felt surgical resection should be delayed until results returned given potential effect on ECR decisions. CONCLUSION: Inconsistencies in who is felt should order MSI/IHC may lead to diffusion of responsibility, preventing consistent testing, including preoperatively. Assuring institutional universal testing protocols are in place, with focus on timing of testing, can optimize care. Strategies addressing cost barriers and genomic service availability in rural and non-academic settings can enhance testing. Greater emphasis on guideline familiarity is required.

Cost-Effectiveness Analysis of Diagnosis of Duchenne/Becker Muscular Dystrophy in Colombia.

OBJECTIVES: To determine the cost-effectiveness ratio of different courses of action for the diagnosis of Duchenne or Becker muscular dystrophy in Colombia. METHODS: The cost-effectiveness analysis was performed from the Colombian health system perspective. Decision trees were constructed, and different courses of action were compared considering the following tests: immunohistochemistry (IHC), Western blot (WB), multiplex polymerase chain reaction, multiplex ligation-dependent probe amplification (MLPA), and the complete sequencing of the dystrophin gene. The time horizon matched the duration of sample extraction and analysis. Transition probabilities were obtained from a systematic review. Costs were constructed with a type-case methodology using the consensus of experts and the valuation of resources from consulting laboratories and the 2001 Social Security Institute cost manual. Deterministic sensitivity and scenario analyses were performed with one or more unavailable alternatives. Costs were converted from Colombian pesos to US dollars using the 2014 exchange rate. RESULTS: In the base case, WB was the dominant strategy, with a cost of US $419.07 and a sensitivity of 100%. This approach remains the dominant strategy down to a 98.2% sensitivity and while costs do not exceed US $837.38. If WB was not available, IHC had the best cost-effectiveness ratio, followed by MLPA and sequencing. CONCLUSIONS: WB is a cost-effective alternative for the diagnosis of patients suspected of having Duchenne or Becker muscular dystrophy in the Colombian health system. The IHC test is rated as the second-best detection method. If these tests are not available, MLPA followed by sequencing would be the most cost-effective alternative.

[Immunohistochemistry using clone VE1 is an economic, specific and sensitive method for detecting the presence of BRAFV600E mutations in melanoma]. / L'immunohistochimie (clone VE1) est une méthode économique, spécifique et sensible pour détecter la présence d'une mutation BRAFV600E dans le mélanome.

BACKGROUND: Determination of BRAF mutation status is mandatory in the management of patients with inoperable stage IIIC or stage IV melanoma. Currently, molecular biology (MB) has been validated for detecting the presence of BRAF mutations. OBJECTIVE: To compare the sensitivity, specificity and cost of immunohistochemistry (IHC) (clone VE1) versus BM methods (qPCR and Sanger sequencing). PATIENTS AND METHODS: All the samples for which BRAF mutation status was requested between March 2013 and February 2015 at the cellular and molecular analysis laboratory of the Angers Hospital were included retrospectively and consecutively. The IHC (clone VE1) and BM analyses were performed with the same formalin-fixed paraffin embedded tumour samples. The cost of these two methods was determined on the basis of the cost for the French Health Insurance. RESULTS: Two hundred and seven samples were subjected to a determination of BRAF mutational status in IHC and BM. Only one sample was discordant between these two methods (positive in IHC, negative in BM). The sensitivity and specificity of the IHC was 100% and 99.25% respectively. The ratio of the cost of IHC/BM testing was 1:2.1. CONCLUSION: IHC (clone VE1) is a specific, sensitive and economic method for determining BRAFV600E mutation status. Nevertheless, this method must be validated in order to be integrated into a decisional algorithm, alongside BM methods, to determine whether targeted BRAF-inhibitor therapy is indicated.

A new scenario in the immunohistochemical diagnosis of cutaneous leishmaniasis.

Cutaneous lesions of leishmaniasis are easy to diagnose when clinically obvious or when amastigotes are numerous in the biopsy. However, this is not always the case. In difficult cases, the diagnosis of leishmaniasis requires a reliable tool to identify the microorganisms. The identification of the parasite via microscope has a superior sensitivity to that of culture, and molecular techniques, such as polymerase chain reaction (PCR), highly improve the sensitivity of the diagnosis. Alternatively, immunohistochemistry has emerged as an affordable alternative to PCR. Several laboratories have produced their own antibodies against Leishmania and seem satisfied with the results. Nevertheless, most of these antibodies are not commercialized or standardized. Pathology also welcomed the unexpected positivity of amastigotes with certain clones of anti-CD1a. The latter does not universally stain all species of Leishmania, with a low sensitivity for New World species. In conclusion, although anti-CD1a is a reliable complementary tool in the diagnosis of leishmaniasis, pathologists should familiarize themselves with one of the specific antibodies against Leishmania and globalize its use, standardizing and adapting the technique.

Quality control in diagnostic immunohistochemistry: integrated on-slide positive controls.

Standardization in immunohistochemistry is a priority in modern pathology and requires strict quality control. Cost containment has also become fundamental and auditing of all procedures must take into account both these principles. Positive controls must be routinely performed so that their positivity guarantees the appropriateness of the immunohistochemical procedure. The aim of this study is to develop a low cost (utilizing a punch biopsy-PB-tool) procedure to construct positive controls which can be integrated in the patient's tissue slide. Sixteen frequently used control blocks were selected and multiple cylindrical samples were obtained using a 5-mm diameter punch biopsy tool, separately re-embedding them in single blocks. For each diagnostic immunoreaction requiring a positive control, an integrated PB-control section (cut from the appropriate PB-control block) was added to the top right corner of the diagnostic slide before immunostaining. This integrated control technique permitted a saving of 4.75% in total direct lab costs and proved to be technically feasible and reliable. Our proposal is easy to perform and within the reach of all pathology labs, requires easily available tools, its application costs is less than using external paired controls and ensures that a specific control for each slide is always available.

Sustainable Development of Pathology in Sub-Saharan Africa: An Example From Ghana.

CONTEXT: - Pathology services are poorly developed in Sub-Saharan Africa. Komfo Anokye Teaching Hospital in Kumasi, Ghana, asked for help from the pathology department of the University Hospital of North Norway, Tromsø. OBJECTIVE: - To reestablish surgical pathology and cytology in an African pathology department in which these functions had ceased completely, and to develop the department into a self-supporting unit of good international standard and with the capacity to train new pathologists. DESIGN: - Medical technologists from Kumasi were trained in histotechnology in Norway, they were returned to Kumasi, and they produced histologic slides that were temporarily sent to Norway for diagnosis. Two Ghanaian doctors received pathology training for 4 years in Norway. Mutual visits by pathologists and technologists from the 2 hospitals were arranged for the introduction of immunohistochemistry and cytology. Pathologists from Norway visited Kumasi for 1 month each year during 2007-2010. Microscopes and immunohistochemistry equipment were provided from Norway. Other laboratory equipment and a new building were provided by the Ghanaian hospital. RESULTS: - The Ghanaian hospital had a surgical pathology service from the first project year. At 11 years after the start of the project, the services included autopsy, surgical pathology, cytopathology, frozen sections, and limited use of immunohistochemistry, and the department had 10 residents at different levels of training. CONCLUSIONS: - A Ghanaian pathology department that performed autopsies only was developed into a self-supported department with surgical pathology, cytology, immunohistochemistry, and frozen section service, with an active residency program and the capacity for further development that is independent from assistance abroad.

Immunohistochemical detection of the BRAF V600E mutation in papillary thyroid carcinoma. Evaluation against real-time polymerase chain reaction. / Detección inmunohistoquímica de la mutación BRAF V600E en el carcinoma papilar de tiroides. Evaluación frente a la reacción en cadena de la polimerasa en tiempo real.

INTRODUCTION: The BRAF V600E mutation is the most common genetic change in papillary thyroid carcinoma and is associated with a poorer clinical course. Usual methods for its study (DNA sequencing or molecular test based on PCR) are expensive and time-consuming. Recently, immunohistochemistry (IHC) for BRAF mutation has been introduced. OBJECTIVE: To compare the results of IHC and real time PCR (RT-PCR) in the detection of BRAF V600E mutation in papillary thyroid carcinoma. Analysis of clinical and pathological differences depending on RT-PCR results is included. METHODS: A prospective study was performed in 82 consecutive samples, 54 of them taken through a core needle biopsy. IHC was performed on tissue fixed for 24hours with 10% neutral formalin using the anti-BRAF V600E (VE-1) mouse monoclonal primary antibody and was rated as positive or negative. DNA was extracted from formalin-fixed, paraffin-embedded tissues by manual microdissection, and BRAF mutation was detected by RT-PCR using the Cobas® 4800 BRAF V600 mutation test (Roche). RESULTS: Both techniques were concordant in 81 cases, and BRAF was positive in 49. Discordance appeared in a follicular variant showing positive IHC and negative RT-PCR, attributed to histological heterogeneity. Cost of materials for IHC was less than half of the cost for RT-PCR. CONCLUSIONS: IHC appears to be a reliable, economical and easily available alternative to molecular biology techniques for routine detection of the BRAF V600E mutation in papillary thyroid carcinoma patients, provided optimal fixation conditions are used. It may be a useful technique in hospitals with no access to molecular biology techniques.

Immunohistochemistry for EGFR Mutation Detection in Non-Small-Cell Lung Cancer.

INTRODUCTION: The sensitivity and specificity of immunohistochemistry (IHC) was compared with the standard polymerase chain reaction (PCR)-based method for detecting common activating epidermal growth factor receptor (EGFR) mutations in non-small-cell lung cancer (NSCLC). Additionally, we evaluated predictive value of IHC EGFR mutation-positive status for EGFR tyrosine kinase inhibitor (TKI) treatment outcome and estimated cost-effectiveness for the upfront IHC testing. METHODS: The trial included 79 consecutive EGFR mutation-positive and 29 EGFR mutation-negative NSCLC cases diagnosed with reflex PCR-based testing. Two mutation-specific antibodies against the most common exon 19 deletion, namely E746-A750del (clone SP111) and L858R mutation (clone SP125) were tested by using automated immunostainer. Sixty of 79 EGFR mutation-positive cases were treated with EGFR TKIs for advanced disease and included in treatment outcome analysis. A decision tree was used for the cost-effectiveness analysis. RESULTS: The overall sensitivity and specificity of the IHC-based method compared with the PCR-based method were 84.8% (95% confidence interval [CI] 74.6-91.6) and 100% (95% CI 85.4-100), respectively. The median progression-free survival (PFS) and overall survival (OS) of patients with IHC-positive EGFR mutation status were highly comparable to the total cohort (PFS: 14.3 vs. 14.0 months; OS: 34.4 vs. 34.4 months). The PCR and IHC cost ratio needs to be approximately 8-to-1 and 4-to-1 in White and Asian populations, respectively, to economically justify upfront use of IHC. CONCLUSION: The trial confirmed an excellent specificity with fairly good sensitivity of IHC with mutation-specific antibodies for common EGFR mutations and the accuracy of IHC testing for predicting response to EGFR TKIs. The use of upfront IHC depends mainly on the population EGFR mutation positivity probability.