Comparative evaluation of non-informative HER-2 immunoreactions (2+) in breast carcinomas with FISH, CISH and QRT-PCR

Circulating microRNAs can predict chemotherapy-induced toxicities in patients being treated for primary breast cancer

PURPOSE

Prescribing NAC for breast cancer is a pragmatic treatment strategy for several reasons; however, certain patients suffer chemotherapy-induced toxicities. Unfortunately, identifying patients at risk of toxicity often proves challenging. MiRNAs are small non-coding RNA molecules which modulate genetic expression. The aim of this study was to determine whether circulating miRNAs are sensitive biomarkers that can identify the patients likely to suffer treatment-related toxicities to neoadjuvant chemotherapy (NAC) for primary breast cancer.

METHODS

This secondary exploratory from the prospective, multicentre translational research trial (CTRIAL ICORG10/11-NCT01722851) recruited 101 patients treated with NAC for breast cancer, from eight treatment sites across Ireland. A predetermined five miRNAs panel was quantified using RQ-PCR from patient bloods at diagnosis. MiRNA expression was correlated with chemotherapy-induced toxicities. Regression analyses was performed using SPSS v26.0.

RESULTS

One hundred and one patients with median age of 55 years were recruited (range: 25-76). The mean tumour size was 36 mm and 60.4% had nodal involvement (n = 61) Overall, 33.7% of patients developed peripheral neuropathies (n = 34), 28.7% developed neutropenia (n = 29), and 5.9% developed anaemia (n = 6). Reduced miR-195 predicted patients likely to develop neutropenia (P = 0.048), while increased miR-10b predicted those likely to develop anaemia (P = 0.049). Increased miR-145 predicted those experiencing nausea and vomiting (P = 0.019), while decreased miR-21 predicted the development of mucositis (P = 0.008).

CONCLUSION

This is the first study which illustrates the value of measuring circulatory miRNA to predict patient-specific toxicities to NAC. These results support the ideology that circulatory miRNAs are biomarkers with utility in predicting chemotherapy toxicity as well as treatment response.

Evaluating the Role of Circulating MicroRNAs in Predicting Long-Term Survival Outcomes in Breast Cancer: A Prospective, Multicenter Clinical Trial

BACKGROUND

While long-term outcomes have improved for patients with breast cancer, 20% to 30% will still develop recurrence, and identifying these patients remains a challenge. MicroRNAs (miRNAs) are small, noncoding molecules that modulate genetic expression and affect oncogenesis.

STUDY DESIGN

This prospective, multicenter trial (ICORG10/11-NCT01722851) recruited patients undergoing neoadjuvant chemotherapy across 8 Irish centers. Predetermined miRNAs were quantified from patient whole blood using quantitative reverse transcriptase polymerase chain reaction. Venous sampling was performed at diagnosis (timepoint 1) and midway during neoadjuvant chemotherapy (timepoint 2 [T2]). miRNA expression profiles were correlated with recurrence-free survival (RFS), disease-free survival (DFS), and overall survival. Data analysis was performed using R v3.2.3.

RESULTS

A total of 124 patients were recruited with a median age of 55.0 years. The median follow-up was 103.1 months. Increased miR-145 expression at T2 was associated with improved RFS (hazard ratio 0.00; 95% confidence interval [CI] 0.00 to 0.99; p = 0.050). Using survival regression tree analysis, a relative cutoff of increased miR-145 expression greater than 0.222 was associated with improved RFS (p = 0.041). Increased miR-145 expression at T2 trended towards significance in predicting improved DFS (hazard ratio 0.00; 95% CI 0.00 to 1.42; p = 0.067). Using survival regression tree analysis, a relative cutoff of increased miR-145 expression greater than 0.222 was associated with improved DFS (p = 0.012). No miRNAs correlated with overall survival.

CONCLUSIONS

ICORG10/11 is the first Irish multicenter, translational research trial evaluating circulatory miRNAs as biomarkers predictive of long-term survival and correlated increased miR-145 expression with enhanced outcomes in early-stage breast cancer. Validation of these findings is required in the next generation of translational research trials.

A Novel Surrogate Nomogram Capable of Predicting OncotypeDX Recurrence Score©

Background: OncotypeDX Recurrence Score© (RS) is a commercially available 21-gene expression assay which estimates prognosis and guides chemoendocrine prescription in early-stage estrogen-receptor positive, human epidermal growth factor receptor-2-negative (ER+/HER2−) breast cancer. Limitations of RS testing include the cost and turnaround time of several weeks. Aim: Our aim is to develop a user-friendly surrogate nomogram capable of predicting RS. Methods: Multivariable linear regression analyses were performed to determine predictors of RS and RS > 25. Receiver operating characteristic analysis produced an area under the curve (AUC) for each model, with training and test sets were composed of 70.3% (n = 315) and 29.7% (n = 133). A dynamic, user-friendly nomogram was built to predict RS using R (version 4.0.3). Results: 448 consecutive patients who underwent RS testing were included (median age: 58 years). Using multivariable regression analyses, postmenopausal status (β-Coefficient: 0.25, 95% confidence intervals (CIs): 0.03−0.48, p = 0.028), grade 3 disease (β-Coefficient: 0.28, 95% CIs: 0.03−0.52, p = 0.026), and estrogen receptor (ER) score (β-Coefficient: −0.14, 95% CIs: −0.22−−0.06, p = 0.001) all independently predicted RS, with AUC of 0.719. Using multivariable regression analyses, grade 3 disease (odds ratio (OR): 5.67, 95% CIs: 1.32−40.00, p = 0.037), decreased ER score (OR: 1.33, 95% CIs: 1.02−1.66, p = 0.050) and decreased progesterone receptor score (OR: 1.16, 95% CIs: 1.06−1.25, p = 0.002) all independently predicted RS > 25, with AUC of 0.740 for the static and dynamic online nomogram model. Conclusions: This study designed and validated an online user-friendly nomogram from routinely available clinicopathological parameters capable of predicting outcomes of the 21-gene RS expression assay.

Relationship Study of The Verified H uman Epidermal Growth Factor Receptor 2 Amplification with Other Tumor Markers and Clinicohistopathological Characteristics in Patients with Invasive Breast Cancer, Using Chromogenic In Situ Hybridization

Objective

Human epidermal growth factor receptor 2 (HER-2), as a crucial factor involved in about 20% of breast cancer cases, is one of the most reliable tumor markers to determine prognosis and therapeutic trend of this disease. This marker is generally assessed by immunohistochemistry (IHC) technique. In the cases that result of IHC test cast doubt (+2), the test should be repeated or validated by applying in situ hybridization techniques, like chromogenic in situ hybridization (CISH). In this regard, the goal of current study was to figure out the link between different clinicopathological characteristics of patients suffering from invasive breast cancer, using tumor markers, hormone receptor (HR) and HER-2. Comparing IHC and CISH techniques for evaluating diagnostic value and usefulness of HER-2 were also the other objective of this study.

Materials and Methods

Based on this retrospective study, histological markers of 113 individuals suffering from invasive breast cancer -such as estrogen receptor (ER), progesterone receptor, HER-2 receptor, E-cadherin, CK5/6, vimentin and Ki67 were examined by IHC technique. HER-2 amplification of all patients was also evaluated by CISH. Clinicopathological information of the patients was also extracted from medical documents and their associations with tumor markers were statistically evaluated.

Results

There is a significant relationship between tumor size, CK5/6 and tumor grade with HR status. Similar relationship was observed between HER-2 status and HR status, as well as vascular invasion (P<0.05). The comparison of HER-2 amplification showed no complete concordance of the result obtained from these two techniques, with score +3.

Conclusion

Since the status of HER-2 is very important in decision making of the treatment process, CISH technique is recommended in the malignant conditions as the primary test, instead of IHC. In this study, we also determined that HER-2 expression is greatly correlated with ER- and PR- status. This might propose a better prognosis for HER-2⁺ patients.

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.

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.

Clinical utility of RT-PCR in assessing HER 2 gene expression versus traditional IHC and FISH in breast cancer patients

BACKGROUND

IHC and FISH are used for categorizing HER 2 status in breast cancer at the protein and DNA level, respectively. HER 2 expression at the RNA level is quantitative, cheaper, easier to standardize and free from interobserver variation.

METHODS

115 consecutive patients were tested by IHC, FISH and RT-PCR (test cohort). Assuming FISH result to be the response variable, ROC curves for RT-PCR ratio were analyzed to label HER 2 negative, equivocal and positive cases as RT-PCR score 1, 2 and 3, respectively. Inter-relationships between RT-PCR, IHC and FISH were defined. 'Clinical benefit' of a test was defined as proportion of patients labeled unequivocally as HER 2 positive or negative. Population for 1 year was simulated constraint to previous reports of HER 2 positivity and IHC category distribution by a meta-analysis of previous studies that evaluated concordance between IHC and FISH to determine HER 2 status (simulation cohort). Four diagnostic pathways in the simulation cohort were defined-(1) initial IHC, followed by FISH (conventional pathway); (2) initial RT-PCR, followed by FISH; (3) initial IHC, followed by RT-PCR and then by FISH; (4) initial RT-PCR, followed by IHC and then by FISH. The clinical benefit of IHC and RT-PCR in the four pathways was analyzed and sensitivity analysis for incremental cost-effectiveness ratio and cost-benefit comapring RT-PCR against IHC, both as first-line tests and among those with IHC score 2 as a reflex second-line test was performed by the Monte Carlo technique.

FINDINGS

115 patients comprised the study population. While none with IHC score of 0 or 1 was FISH positive for HER 2, all cases with IHC score of 3 were FISH positive. 43 cases were assigned IHC score of 2. Thus, 72 patients benefited from the initial IHC testing [clinical benefit 62.6%], with the overall concordance between IHC and FISH being 100% for those with IHC score of 0, 1 and 3 (conclusive IHC categories). For RT-PCR with 100% concordance, 15.7% (115-97 = 18) patients would have benefited from RT-PCR testing if it was used as a first-line test. If RT-PCR would have been used as a second-line test among those with IHC score 2 (n = 43), then only 6 patients would have been assigned a conclusive RT-PCR category (category 1 or 3) translating to a clinical benefit of 14% (6/43) as a second-line test. As a second-line test it had 51% probability to prove more cost-effective than the conventional pathway, provided the cost of RT-PCR was 0.4 times the cost of IHC. Also in a three-step pathway, RT-PCR upfront would have 56% probability of higher cost-benefit provided the cost of RT-PCR was 0.1 times the cost of IHC.

CONCLUSION

RT-PCR results were found to be suboptimal to IHC in terms of discriminative ability and clinical benefit; thus, it is unlikely to replace IHC as a first-line test in the near future.

Her2 assessment using quantitative reverse transcriptase polymerase chain reaction reliably identifies Her2 overexpression without amplification in breast cancer cases

BACKGROUND

Immunohistochemistry (IHC) and fluorescent-in situ hybridization (FISH) are standard methods to assess human epidermal growth factor receptor 2 (HER2) status in breast cancer (BC) patients. Real-time quantitative polymerase-chain-reaction (qRT-PCR) is able to detect HER2 overexpression. Here we compared FISH, IHC, quantitative PCR (qPCR), and qRT-PCR to determine the concordance rates and evaluate their relative roles in HER2 determination.

PATIENTS AND METHODS

We determined HER2 status in 153 BC patients, using IHC, FISH, Q-PCR and qRT-PCR. In discordant cases, we directly measured HER2 protein levels using Western blotting.

RESULTS

The overall agreement (OA) between FISH and Q-PCR was 94.1, with a k value of 0.87. Assuming FISH as the standard reference, Q-PCR showed an 86.1% sensitivity and a 99.0% specificity with a global accuracy of 91.6%. OA between FISH and qRT-PCR was 90.8% with a k value of 0.81. Of interest, the disagreement between FISH and qRT-PCR was mostly restricted to equivocal cases. HER2 protein analysis suggested that qRT-PCR correlates better than FISH with HER2 protein levels, particularly where FISH fails to provide conclusive results.

SIGNIFICANCE

qRT-PCR may outperform FISH in identifying patients overexpressing HER2 protein. Q-PCR cannot be used for HER2 status assessment, due to its suboptimal level of agreement with FISH. Both FISH and Q-PCR may be less accurate than qRT-PCR as surrogates of HER2 protein determination.

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.

Chromogenic in situ hybridization compared with other approaches to evaluate HER2/neu status in breast carcinomas

Human epidermal growth factor receptor 2 (HER2) has been evaluated in breast cancer patients to identify those most likely to benefit from herceptin-targeted therapy. HER2 amplification, detected in 20-30% of invasive breast tumors, is associated with reduced survival and metastasis. The most frequently used technique for evaluating HER2 protein status as a routine procedure is immunohistochemistry (IHC). HER2 copy number alterations have also been evaluated by fluorescence in situ hybridization (FISH) in moderate immunoexpression (IHC 2+) cases. An alternative procedure to evaluate gene amplification is chromogenic in situ hybridization (CISH), which has some advantages over FISH, including the correlation between HER2 status and morphological features. Other methodologies have also been used, such as silver-enhanced in situ hybridization (SISH) and quantitative real-time RT-PCR, to determine the number of HER2 gene copies and expression, respectively. Here we will present a short and comprehensive review of the current advances concerning HER2 evaluation in human breast cancer.

Microfluidic processor allows rapid HER2 immunohistochemistry of breast carcinomas and significantly reduces ambiguous (2+) read-outs

Biomarker analysis is playing an essential role in cancer diagnosis, prognosis, and prediction. Quantitative assessment of immunohistochemical biomarker expression on tumor tissues is of clinical relevance when deciding targeted treatments for cancer patients. Here, we report a microfluidic tissue processor that permits accurate quantification of the expression of biomarkers on tissue sections, enabled by the ultra-rapid and uniform fluidic exchange of the device. An important clinical biomarker for invasive breast cancer is human epidermal growth factor receptor 2 [(HER2), also known as neu], a transmembrane tyrosine kinase that connotes adverse prognostic information for the patients concerned and serves as a target for personalized treatment using the humanized antibody trastuzumab. Unfortunately, when using state-of-the-art methods, the intensity of an immunohistochemical signal is not proportional to the extent of biomarker expression, causing ambiguous outcomes. Using our device, we performed tests on 76 invasive breast carcinoma cases expressing various levels of HER2. We eliminated more than 90% of the ambiguous results (n = 27), correctly assigning cases to the amplification status as assessed by in situ hybridization controls, whereas the concordance for HER2-negative (n = 31) and -positive (n = 18) cases was 100%. Our results demonstrate the clinical potential of microfluidics for accurate biomarker expression analysis. We anticipate our technique will be a diagnostic tool that will provide better and more reliable data, onto which future treatment regimes can be based.

Breast cancer subtypes identified by the ER, PR and HER-2 status in Thai women

Expression of estrogen-receptor (ER), progesterone-receptor (PR) and HER-2 has recently been linked with various breast cancer subtypes identified by gene microarray. This study aimed to document breast cancer subtypes based on ER, PR and HER-2 status in Thai women, where expression of these subtypes may not be similar to those evident in Western women. During 2009 to 2010, histological findings from 324 invasive ductal carcinomas (IDC) at Siriraj Hospital were studied. Various subtypes of IDC were identified according to expression of ER, PR and HER-2: luminal-A (ER+;PR+/-;HER-2-), luminal-B (ER+;PR+/-;HER-2+), HER-2 (ER-;PR- ;HER-2+) and basal-like (ER-;PR-;HER-2-). As well, associations of tumor size, tumor grade, nodal status, angiolymphatic invasion (ALI), multicentricity and multifocality with different breast cancer subtypes were studied. Of 324 IDCs, 143 (44.1%), 147 (45.4%), 15 (4.6%) and 12 (3.7%) were T1, T2, T3 and T4, respectively. Most tumors were grade 2 (54.9%) and had no nodal involvement (53.4%). According to ER, PR and HER-2 status, 192 (59.3%), 40 (12.3%), 43 (13.3%) and 49 (15.1%) tumors were luminal-A, luminal-B, HER-2 and basal-like subtypes. HER-2 subtype presented with large tumor (p=0.04, ANOVA). Luminal-A IDC was associated with single foci (p<0.01, χ2). HER-2 and basal-like subtypes were likely to have high tumor grade (p<0.01, χ2). In addition, HER-2 subtype had higher number of nodal involvement (p=0.048, χ2). In conclusion, the luminal-A subtype accounted for the majority of IDCs in Thai women. Percentages of HER-2 and basal-like IDCs were high, compared with a recent study from the USA. The HER-2 subtype was related with high nodal invasion. The findings may highlight biological differences between IDCs occurring in Asian and Western women.

Immunohistochemical and molecular analyses of HER2 status in breast cancers are highly concordant and complementary approaches

Background:

Immunohistochemistry (IHC) and fluorescent in situ hybridisation (FISH) are currently the most commonly used methods to assess HER2 status. PCR-based assays allow quantitative determination of HER2 amplification (Q-PCR) or overexpression (Q-RT–PCR), but are not routinely used. We evaluated the relevance of Q-RT–PCR for HER2 status determination.

Methods:

We compared IHC and Q-RT–PCR in 466 breast tumours. In discordant or equivocal cases, five additional methods (IHC with two other antibodies, FISH, silver in situ hybridisation (SISH) and Q-PCR) were combined to determine HER2 status. Two cases with HER2 intra-tumour heterogeneity were further explored by allelic profiles analysis and HUMARA clonality determination after microdissection.

Results:

We observed 97.3% concordance between Q-RT–PCR and non-equivocal IHC. Twelve out of 466 cases (3%) revealed discordances between the two methods. The power of Q-RT–PCR to predict HER2 status (defined by seven methods) was similar to that of IHC. Although rare, some discordances between techniques might be due to HER2 intra-tumour heterogeneity and we report two examples, one tumour containing two distinct clones, another tumour consisting of HER2 amplified and non-amplified subclones.

Conclusion:

Q-RT–PCR and IHC are highly concordant methods for HER2 status assessment, and Q-RT–PCR allows a highly reliable quantitative assessment and could be a useful adjunct to IHC.

Current technologies for HER2 testing in breast cancer

BACKGROUND

Molecular techniques play an increasingly important role in breast cancer detection and help in the prediction of prognosis and treatment response. HER-2/neu predicts the sensitivity of breast tumors to trastuzumab and lapatinib. Presently there are several ways to assess HER2 status at the protein level (e.g. ELISA), at the RNA level (RT-PCR, microarray) and at the DNA level (fluorescence in situ hybridization, chromogenic in situ hybridization (ISH), silver in situ hybridization or multiplex ligation-dependent probe amplification).

DESIGN

This paper provides an overview of new developments in HER2 testing.

RESULTS

Although these techniques correlate well in comparative studies, discrepancies remain. Each technique has its own (dis)advantages and thus there is no real gold standard. Not surprisingly, there is no consensus at present on which of the protein- or gene-based techniques is superior, on the use of mono- or duo-probe ISH systems, nor on the use of manual or fully-automated staining- and scoring systems.

CONCLUSION

Until large clinical trials clearly point out one strategy as the best predictive one for trastuzumab response, the choice for a testing strategy will probably be based on local preferences which consider both practical and economic issues. Standardization, proper internal and external quality control assessment, laboratory accreditation and automation of tissue processing (autostainers) and interpretation methods (image analysis) will play an increasingly important role in HER2 testing.

Performance of chromogenic in situ hybridization on testing HER2 Status in breast carcinomas with chromosome 17 polysomy and equivocal (2+) herceptest results: a study of two institutions using the conventional and new ASCO/CAP scoring criteria

This study specifically addressed the performance of chromogenic in situ hybridization (CISH) on HER2 testing in 66 breast carcinomas with chromosome 17 polysomy and 49 carcinomas with an equivocal HercepTest (DakoCytomation, Carpinteria, CA) score by comparing CISH with corresponding FISH results at 2 test sites and evaluating intersite agreement of CISH results. For tumors with chromosome 17 polysomy, when using the manufacturers' criteria, the concordance values between CISH and FISH at site A, site B, and intersite CISH agreement were 95.8%, 95.5%, and 93.5%, respectively; when using the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) criteria, the values were 100.0%, 100.0%, and 100.0%, respectively. For tumors with an equivocal HercepTest score, when using the manufacturers' criteria, the concordance values between the 2 methods at site A, site B, and intersite CISH agreement were 88.2%, 95.1%, and 91.1%, respectively; when using the ASCO/CAP criteria, the values were 96.7%, 97.3%, and 97.4%, respectively. These results indicate that CISH is reliable for testing these 2 types of tumors, especially when the ASCO/CAP criteria are used.

A single-tube quantitative assay for mRNA levels of hormonal and growth factor receptors in breast cancer specimens

Knowledge of estrogen receptor (ER) and progesterone receptor (PR) status has been critical in the evolution of modern targeted therapy of breast cancer and remains essential for making informed therapeutic decisions. Recently, growth factor receptor HER2/neu (ERBB2) status has made it possible to provide another form of targeted therapy linked to the overexpression of this protein. Presently, pathologists determine the receptor status in formalin-fixed, paraffin-embedded sections using subjective, semiquantitative immunohistochemistry (IHC) assays and quantitative fluorescence in situ hybridization for HER2. We developed a single-tube multiplex TaqMan (mERPR+HER2) assay to quantitate mRNA levels of ER, PR, HER2, and two housekeeping genes for breast cancer formalin-fixed, paraffin-embedded sections. Using data from the discovery sample sets, we evaluated IHC-status-dependent cutoff-point and IHC-status-independent clustering methods for the classification of receptor status and then validated these results with independent sample sets. Compared with IHC-status, the accuracies of the mERPR+HER2 assay with the cutoff-point classification method were 0.98 (95% CI: 0.97-1.00), 0.92 (95% CI: 0.88-0.95), and 0.97 (95% CI: 0.95-0.99) for ER, PR, and HER2, respectively, for the validation sets. Furthermore, the areas under the receiver operating-characteristic curves were 0.997 (95% CI: 0.994-1.000), 0.967 (95% CI: 0.949-0.985), and 0.968 (95% CI: 0.915-1.000) for ER, PR, and HER2, respectively. This multiplex assay provides a sensitive and reliable method to quantitate hormonal and growth factor receptors.

Quantitative real-time RT-PCR and chromogenic in situ hybridization: precise methods to detect HER-2 status in breast carcinoma

Background

HER-2 gene testing has become an integral part of breast cancer patient diagnosis. The most commonly used assay in the clinical setting for evaluating HER-2 status is immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). These procedures permit correlation between HER-2 expression and morphological features. However, FISH signals are labile and fade over time, making post-revision of the tumor difficult. CISH (chromogenic in situ hybridization) is an alternative procedure, with certain advantages, although still limited as a diagnostic tool in breast carcinomas.

Methods

To elucidate the molecular profile of HER-2 status, mRNA and protein expression in 75 invasive breast carcinomas were analyzed by real time quantitative RT-PCR (qRT-PCR) and IHC, respectively. Amplifications were evaluated in 43 of these cases by CISH and in 11 by FISH.

Results

The concordance rate between IHC and qRT-PCR results was 78.9%, and 94.6% for qRT-PCR and CISH. Intratumoral heterogeneity of HER-2 status was identified in three cases by CISH. The results of the three procedures were compared and showed a concordance rate of 83.8%; higher discordances were observed in 0 or 1+ immunostaining cases, which showed high-level amplification (15.4%) and HER-2 transcript overexpression (20%). Moreover, 2+ immunostaining cases presented nonamplified status (50%) by CISH and HER-2 downexpression (38.5%) by qRT-PCR. In general, concordance occurred between qRT-PCR and CISH results. A high concordance was observed between CISH/qRT-PCR and FISH. Comparisons with clinicopathological data revealed a significant association between HER-2 downexpression and the involvement of less than four lymph nodes (P = 0.0350).

Conclusion

Based on these findings, qRT-PCR was more precise and reproducible than IHC. Furthermore, CISH was revealed as an alternative and useful procedure for investigating amplifications involving the HER-2 gene.

Phenotypic mismatch repair hMSH2 and hMLH1 gene expression profiles in primary non-small cell lung carcinomas

BACKGROUND

Defects in the human DNA mismatch repair genes (MMR) hMSH2 and hMLH1 are responsible for the development of sporadic and hereditary colorectal cancers. The role of MMR genes in the pathogenesis of lung cancer has not been elucidated. The aim of this study was to address the phenotypic mRNA expression profiles of mismatch DNA repair system in lung cancer.

MATERIALS AND METHODS

We evaluated the mRNA levels of the hMSH2 and hMLH1 components of the mismatch DNA repair (MMR) system in 29 unselected frozen pairs of primary non-small cell lung carcinomas (NSCLCs) and their adjacent normal tissue (ANTs) specimens by quantitative real-time PCR analysis relative to housekeeping Porphobilinogen deaminase (hPBGD) mRNA. To simplify and potentially improve the analysis of data, we defined for each individual MMR mRNA two possible phenotypes: a regular (R(2): hMSH2/hPBGD mRNAs> or =1 and R(1): hMLH1/hPBGD mRNAs> or =1) and a reduced (r(2): hMSH2/hPBGD mRNAs<1 and r(1): hMLH1/hPBGD mRNAs<1). The presence of MMR gene expression was evaluated after conversion of the molecular mRNA levels into clinically distinct phenotypic entities by these working criteria, based on the hypothesis that reduced mRNA and protein levels result in lower or non-functional MMR.

RESULTS

Phenotyping defined four distinct MMR system expression profiles, R(2)R(1), r(2)R(1), R(2)r(1) and r(2)r(1) by ascending tumor progression rate and identified a previously unrecognized disease-associated phenotypic entity (r(2)r(1)). The phenotype-based biological aspects of the MMR system suggested that its two components: (1) function independently and (2) are not directly involved in the onset of the transformation process, since healthy lung tissue was devoid of r(2)r(1) phenotypes.

CONCLUSION

These findings link MMR mRNA levels of paired lung tissue specimens to patients' clinical condition and suggest that phenotypic translation of molecular MMR data refines the biology of the MMR system with consequent diagnostic implications in the clinical assessment of lung cancer patients.

Delineation of HER2 gene status in breast carcinoma by silver in situ hybridization is reproducible among laboratories and pathologists

An automated enzyme metallographic silver in situ hybridization method (SISH) has been reported to successfully determine human epidermal growth factor receptor 2 (HER2) gene amplification. We evaluated the staining and interpretative reproducibility of the HER2 SISH assay at five laboratories and compared SISH results with other in situ hybridization (ISH) methods. The HER2 gene status of 89 breast carcinomas was analyzed in parallel using manual dual-color fluorescence ISH, manual chromogenic ISH, and bright-field automated SISH. A total of 1098 SISH-stained slides were evaluated. For comparison, all specimens were stained by 4B5 immunohistochemistry for HER2 protein expression. Interpretation was performed by pathologists at five different laboratories using the algorithms provided by the manufacturers and the guidelines of American Society of Clinical Oncology/College of American Pathologists. Staining and interpretative reproducibility were measured through the computation of weighted kappa statistics. Following the optimization of SISH staining, 1077/1098 (98%) of slides were evaluable. Excellent reproducibility and efficacy of HER2 SISH staining, and interobserver interpretation (Kw = 0.91), were observed among five sites. For the 89 invasive breast cancer cases, the overall rate of concordance between consensus 4B5 and consensus SISH, fluorescence ISH, and chromogenic ISH was 96.6% (86/89), 97.8% (87/89), and 96.6% (86/89), respectively. Overall concordance between positive and negative SISH and fluorescence ISH results, as well as between individual and consensus positive and negative SISH results, was excellent (P < 0.001).