Chromogenic in situ hybridization (CISH): a novel alternative in screening archival breast cancer tissue samples for HER-2/neu status

Chromogenic in Situ Hybridization Technique versus Immunohistochemistry in Assessment of HER2/neu Status in 448 Iraqi Patients with Invasive Breast Carcinoma

BACKGROUND

The rapidly growing knowledge regarding factors controlling tumour growth, with the new modalities of therapy acting on the biological activity of the tumours draw the attention of most cancer researches nowadays and represent a major focus for clinical oncology practice. For the detection of HER2/neu protein overexpression and gene amplification, immunohistochemistry (IHC) and in-situ hybridisation (ISH) is the recommended techniques, respectively, with high concordance between the two techniques. The current United Kingdom recommendations for HER2/neu testing are either for a two-tier system using IHC with reflex ISH testing in equivocal positive cases, or a one-tier ISH strategy.

AIM

To compare the results of HER2/neu gene status in patients with breast carcinoma obtained by chromogenic in situ hybridisation with those obtained by immunohistochemistry, and to compare these results with hormonal receptors expression by immunohistochemistry and with age of patients.

METHODS

Immunohistochemistry technique was used for evaluation of status of estrogen receptors (ER) and progesterone receptors (PR) and HER2/neu protein expression in 448 Iraqi patients with invasive breast carcinoma with different grades and histological types and then chromogenic in situ hybridization (CISH) technique was applied for all scores of HER2/neu to detect the gene status and compare the results in all negative, equivocal and positive cases by immunohistochemistry (IHC). The cases were referred from different centres, and IHC and CISH techniques were done in central public health laboratory in Baghdad over 28 months, from July 2013 to November 2015. A comparison of the results was made to find the relationship between HER2/neu and hormone receptors status and other clinical parameters like patients age.

RESULTS

The mean age of the study cases was 49.08 years, ranging from 24 to 83 years. Of the 448 cases of breast carcinoma, 44 (9.8%) cases were of score 0 by IHC, none of them (0%) showed HER2/neu gene amplification by CISH. 71(15.8%) cases were of score 1 by IHC, 15 (21.12%) of them showed HER2/neu gene amplification by CISH, all were of low amplification. There were 306 (68.3%) cases of score 2 by IHC, of which 102 (33.33%) cases showed HER2/neu gene amplification by CISH, with 79 (25.81%) of them with low amplification and 23 (7.51%) cases with high amplification, while only one case (0.32%) remained in equivocal category. In score 3, all the 27 (6.0%) cases showed gene amplification with 12 (44.44%) cases with low amplification and 15 (55.55) cases with high amplification with overall percentage of gene amplification in score 3 of 100%. There was a significant inverse relationship between hormone receptors (ER and PR) status and HER2/neu gene amplification. No significant relationship was found between the patient's age and HER2/neu gene amplification.

CONCLUSION

Although immunohistochemistry is a widely used, less expensive and reliable test, we strongly advice performance of chromogenic in situ hybridization in assessment of HER2/neu gene status in all cases diagnosed with breast carcinoma as significant number of cases that were reported as negative by immunohistochemistry showed positive amplification by chromogenic in situ hybridization and can get benefit from anti-HER2 targeted treatments.

The clinical and biological significance of HER2 over-expression in breast ductal carcinoma in situ: a large study from a single institution

BACKGROUND

Previous studies have reported up to 50% of ductal carcinoma in situ (DCIS), is HER2 positive, but the frequency of HER2-positive invasive breast cancer (IBC) is lower. The aim of this study is to characterise HER2 status in DCIS and assess its prognostic value.

METHODS

HER2 status was evaluated in a large series of DCIS (n = 868), including pure DCIS and DCIS associated with IBC, prepared as tissue microarrays (TMAs). HER2 status was assessed using immunohistochemistry (IHC) and chromogenic in situ hybridisation (CISH).

RESULTS

In pure DCIS, HER2 protein was over-expressed in 9% of DCIS (3+), whereas 15% were HER2 equivocal (2+). Using CISH, the final HER2 status was positive in 20%. In mixed DCIS, HER2 amplification of the DCIS component was detected in 15% with amplification in the invasive component of only 12%. HER2-positive DCIS was associated with features of aggressiveness (p < 0.0001) and more frequent local recurrence (p = 0.03). On multivariate analysis, combined HER2+/Ki67+ profile was an independent predictor of local recurrence (p = 0.006).

CONCLUSIONS

The frequency of HER2 positivity in DCIS is comparable to IBC- and HER2-positive DCIS is associated with features of poor prognosis. The majority of HER2 over-expression in DCIS is driven by gene amplification.

ANXA2 expression in African American triple-negative breast cancer patients

PURPOSE

Our aim was to determine the role of Annexin A2 (AnxA2), which we have previously found to contribute to the aggressiveness of TNBC, with AA TNBC patients and clinical outcome.

METHODS

We analyzed TCGA breast cancer database (n = 1098) to observe AnxA2 expression within breast cancer subtypes and is correlation with overall survival. Further, we examined breast tissue specimens (n = 119) through chromogenic in situ hybridization (CISH) and specimen were scored independently by two pathologists in a blinded study.

RESULTS

In our TCGA analysis, high expression of AnxA2 was correlated with poor survival in patients with TNBC. AnxA2 gene expression was not correlated with poor survival in other breast cancer subtypes. AnxA2 average CISH intensity score (CISH score = 0, null expression to 3, high expression) for TNBC was significantly higher in comparison to estrogen receptor and/or progesterone receptor positive, human epidermal growth factor positive, and non-malignant tissues. Furthermore, AnxA2 average score was significantly higher in AA TNBC patients (CISH average score = 2.45 ± 0.3266) in comparison to Caucasian TNBC patients (CISH average score = 1.1 ± 0.4069).

CONCLUSION

AnxA2 is overexpressed in TNBC, implicating AnxA2 as a contributor to the aggressive biology of TNBC in AA women.

Evaluating HER2 Gene Amplification Using Chromogenic In Situ Hybridization (CISH) Method In Comparison To Immunohistochemistry Method in Breast Carcinoma

BACKGROUND:

In patients with breast cancer, HER2 gene expression is of a great importance in reacting to Herceptin treatment. To evaluate this event, immunohistochemistry (IHC) has been done routinely on the basis of scoring it and so the patients were divided into 4 groups. Lately, as there have been disagreements about how to treat score 2 patients, chromogenic in situ hybridization (CISH) and florescence in situ hybridization (FISH) are introduced. Since CISH method is more convenient than FISH for gene amplification study, FISH has been substituted by CISH.

AIM:

The current study is conducted in order to investigate whether using CISH is a better method comparison to IHC method for determines HER2 expression in patients with breast cancer in.

METHODS:

In this cross-sectional descriptive analytical study, information of 44 female patients with invasive ductal breast cancer were gathered from Imam Reza and Omid Hospital in Mashhad. IHC staining was done for all patients in order to determine the level of HER2 expression, and after scoring them into 4 groups of 0, +1, +2 and +3, CISH staining was carried out for all 4 groups. At the end, results from both methods were statistically evaluated using SPSS software V.22.0.

RESULTS:

The average age of patients was 50.2 with the standard deviation of 10.96. Using IHC method was observed that 2.6% (1 patient), 26.3% (10 patients), 65.8% (25 patients) and 5.3% (2 patients) percentage of patients had scores of 0, +1, +2 and +3. On the other hand, CISH method showed 36 patients (90%) with no amplifications and 4 (10%) with sever amplifications. In a comparative study using Fisher’s exact test (p = 0.000), we found a significant relation between IHC method and CISH method indicating that all patients showing severe amplifications in CISH method, owned scores of +2 and +3 in IHC method.

CONCLUSION:

According to the present study and comparing the results with similar previous studies, it can be concluded that CISH method works highly effective in determining HER2 expression level in patients with breast cancer. This method is also able to determine the status of patients with score +2 in IHC for their treatment with herceptin.

Understanding EGFR Signaling in Breast Cancer and Breast Cancer Stem Cells: Overexpression and Therapeutic Implications

Epidermal growth factor receptors (EGFRs/HERs) and downstream signaling pathways have been implicated in the pathogenesis of several malignancies including breast cancer and its resistance to treatment with chemotherapeutic drugs. Consequently, several monoclonal antibodies as well as small molecule inhibitors targeting these pathways have emerged as therapeutic tools in the recent past. However, studies have shown that utilizing these molecules in combination with chemotherapy has yielded only limited success. This review describes the current understanding of EGFRs/HERs and associated signaling pathways in relation to development of breast cancer and responses to various cancer treatments in the hope of pointing to improved prevention, diagnosis and treatment. Also, we review the role of breast cancer stem cells (BCSCs) in disease and the potential to target these cells.

Fluorescent in Situ Hybridization and Real-Time Quantitative Polymerase Chain Reaction to Evaluate HER-2/neu Status in Breast Cancer

BACKGROUND

Breast cancer remains the most common and second lethal cancer in females. HER-2/neu is one of the most important amplified oncogene in breast cancer. The amplification of HER-2 is correlated with decreased survival, metastasis, and early recurrence. The amplification of HER-2/neu gene and synthesis of the protein are reported in 10%-34% of breast cancer cases associated with tumor size, advanced tumor stage, high-grade tumor, young age at diagnosis, absence of steroid hormone receptor, and lymph node involvement.

METHODS

Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) methods are options to evaluate HER-2 expression. The current study aimed at identifying the correlation between FISH and real-time polymerase chain reaction (PCR) in measuring HER-2 expression.

RESULTS

The study investigated the performance of the real-time PCR as measured against FISH method in IHC +2 borderline cases. In a total of 120 IHC 2+ samples, 58.3% were negative and 41.6% positive for HER-2 gene, confirmed by FISH as a gold standard method. The real-time PCR ratio was <1.8 for a majority (82.8%) of the tumor samples with unamplified HER-2 gene by FISH as a gold standard assay.

CONCLUSION

Despite the fact that real-time PCR is a promising method to evaluate HER-2 over expression and a supplementary array to FISH, according to the results of the present study it cannot be utilized instead of gold standard techniques; therefore, additional studies should be carried out to appraise the value of this method to evaluate HER-2 over expression.

Qasim B, A.K. Al Shaikhly A. Evaluation of Immunohistochemistry-Equivocal (2+) HER2 Gene Status in Invasive Breast Cancer by Silver DNA in Situ Hybridization (SISH) and its Association with Clinicopathological Variables

BACKGROUND AND OBJECTIVE

Determination of HER2 gene is crucial in breast carcinoma management and prognosis, as HER2 alterations are linked to a shorter disease-free period, overall survival and resistance to tamoxifen anti-estrogen therapy and other chemotherapy regimens, regardless of the nodal or hormone receptor status. This study aimed to estimate HER2 gene status of infiltrative mammary cancer cases with immunohistochemically equivocal (2+) score using Silver DNA in Situ Hybridization (SISH) technique and to investigate its association with clinicopathological variables.

METHODS

The study included 52 formalin-fixed paraffin embedded tissue blocks from female patients with invasive breast carcinoma with score of 2+ (equivocal) HER2 immunohistochemistry. All cases were studied by silver DNA in situ hybridization technique (SISH) for the determination of the amplified HER2 DNA.

RESULTS

The SISH technique showed that HER2 gene was not amplified in 33 cases out of 52 (63.5%); while the rest of 19 cases (36.5%) revealed amplified gene status. According to age, HER2 gene status reported non-significant difference in the age groups between cases with amplified and non-amplified gene status (P=0.173). There was a significant negative association between positive Estrogen (ER) and Progesterone (PR) status and HER2 gene amplification (P= 0.002 and 0.017, respectively).

CONCLUSION

More than half of breast carcinoma cases with equivocal HER2 immunoreactivity showed non-amplified gene status; this needs to be considered by oncologists in their management planning of breast cancer. Amplified HER2 gene is significantly associated with negative ER and PR status that affects patients' management protocols and future outcome of the disease.

Human umbilical cord-derived mesenchymal stem cells in acute liver injury: Hepatoprotective efficacy, subchronic toxicity, tumorigenicity, and biodistribution

Umbilical cord-derived mesenchymal stem cells (UC-MSCs) therapy might be an alternative to liver transplantation for acute or chronic liver injury. The aim of this study was to evaluate the efficacy of human UC-MSCs on carbon tetrachloride (CCl₄)-induced acute liver injury. In addition, its toxicity, tumorigenicity, and biodistribution were determined. Significant hepatoprotective effects of hUC-MSCs with decreased levels of hepatocellular necrosis and lobular neutrophilic infiltration were found. Regarding the safety of hUC-MSCs, no serious hUC-MSCs-related changes (body weight, food/water consumption, clinical symptom, urinalysis, hematology, clinical chemistry, organ weight, and histopathology) were observed in a 13-week subchronic toxicity study. In a 26-week tumorigenicity study, no mice developed tumor related to hUC-MSCs transplantation up to 1 × 10⁸ cells/kg. In particular, human mitochondrial sequence detection revealed that most hUC-MSCs were cleared from the major organs of the mice at 13 weeks after transplantation. There was no systemic toxicity or neoplastic finding either. Taken together, these results suggested that hUC-MSCs have great potential for future clinical treatment of acute liver disease.

Chromogenic In Situ Hybridisation Test for Breast Cancer Patients with Equivocal IHC Results--a Study from Iran

BACKGROUND

HER2/neu overexpression on cell membranes of breast cancer cells is due to HER2/neu gene amplification and it is important to identify potential candidates for anti HER2 therapy with trastuzumab. IHC, FISH and CISH are standard FDA approved assays currently used to determine HER2 status in routine practice. The aim of this study was to determine HER2 gene amplification, using the CISH method in breast carcinoma samples which had IHC +2 reactions.

MATERIALS AND METHODS

This study was conducted from 2008- 2010 using 334 consecutive breast carcinoma samples referred from local laboratories to Mehr Hospital. CISH assays were performed for all cases, and IHC tests were also done for determining efficacy and accuracy of local labs. HER2 status in local IHC tests was compared with central IHC and CISH results.

RESULTS

Of 334 breast cancer patients, 16 were negative for HER2 IHC (0, +1), 201 cases were equivocal (+2), and 31 positive (+3). Of 334 referral cases, 88 were CISH positive (26.3%) and 246 were CISH negative (73.7%). Of 201 IHC +2 cases, HER2 gene amplification was observed in 42 cases (kappa: 0.42). A 29.9% concordance was found between local IHC and central IHC. Sensitivity and specificity of local IHC were 90% and 53.8%, respectively.

CONCLUSIONS

Low accuracy of IHC results in local labs was associated with the following factors: using former FDA-approved criteria for HER2 interpretation, utilizing non-validated kits, and lack of any quality assurance program. Therefore, following the new 2014 ASCO/CAP guideline and comprehensive quality assurance should be implemented to ensure accuracy of HER2 testing.

Detection of c-myc amplification in formalin-fixed paraffin-embedded tumor tissue by chromogenic in situ hybridization (CISH)

In situ hybridization (ISH) allows evaluation of genetic abnormalities, such as changes in chromosome number, chromosome translocations or gene amplifications, by hybridization of tagged DNA (or RNA) probes with complementary DNA (or RNA) sequences in interphase nuclei of target tissue. However, chromogenic in situ hybridization (CISH) is also applicable to formalin-fixed, paraffin-embedded (FFPE) tissues, besides metaphase chromosome spreads. CISH is similar to fluorescent in situ hybridization (FISH) regarding pretreatments and hybridization protocols but differs in the way of visualization. Indeed, CISH signal detection is similar to that used in immunohistochemistry, making use of a peroxidase-based chromogenic reaction instead of fluorescent dyes. In particular, tagged DNA probes are indirectly detected using an enzyme-conjugated antibody targeting the tags. The enzymatic reaction of the chromogenic substrate leads to the formation of strong permanent brown signals that can be visualized by bright-field microscopy at 40 × magnification. The advantage of CISH is that it allows the simultaneous observation of gene amplification and tissue morphology and the slides can be stored for a long time.

Accurate assessment of HER2 gene status for invasive component of breast cancer by combination of immunohistochemistry and chromogenic In Situ hybridization

The specimens of ductal carcinoma in situ (DCIS) with early invasion, and specimens collected by core needle biopsy (CNB) tend to contain limited amount of invasive component, so it is imperative to explore a new technique which can assess HER2 gene status accurately for the limited invasive cancer component in these specimens. Dual staining technique of combining immunohistochemistry (IHC) for myoepithelial cells and single or dual probe chromogenic in situ hybridization (CISH) for HER2 gene was performed on routinely processed paraffin sections from 20 cases diagnosed as having DCIS with invasive cancer. Among them, 10 had fluorescence in situ hybridization (FISH)-confirmed amplification of HER2 and 10 had FISH-confirmed non-amplification of HER2. We successfully detected HER2 genetic signals and myoepithelial IHC markers (SMM-HC or CK5/6) simultaneously on a single section in all 20 specimens. Myoepithelial markers and HER2 signals detected by dual staining assay were consistent with those by individual technique performed alone. HER2 gene amplification results determined by dual staining assay were 100% consistent with those of FISH. Dual staining technique which allows simultaneous detection of myoepithelial marker protein and cancerous HER2 gene is feasible, and it has potential to be used in clinical practice for effective determination of HER2 amplification in limited invasive component.

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.

A gene-protein assay for human epidermal growth factor receptor 2 (HER2): brightfield tricolor visualization of HER2 protein, the HER2 gene, and chromosome 17 centromere (CEN17) in formalin-fixed, paraffin-embedded breast cancer tissue sections

BACKGROUND

The eligibility of breast cancer patients for human epidermal growth factor receptor 2 (HER2)-directed therapies is determined by the HER2 gene amplification and/or HER2 protein overexpression status of the breast tumor as determined by in situ hybridization (ISH) or immunohistochemistry (IHC), respectively. Our objective was to combine the US Food and Drug Administration (FDA)-approved HER2 & chromosome 17 centromere (CEN17) brightfield ISH (BISH) and HER2 IHC assays into a single automated HER2 gene-protein assay allowing simultaneous detection of all three targets in a single tissue section.

METHODS

The HER2 gene-protein assay was optimized using formalin-fixed, paraffin-embedded (FFPE) samples of the xenograft tumors MCF7 [HER2 negative (non-amplified gene, protein negative)] and Calu-3 [HER2 positive (amplified gene, protein positive)]. HER2 IHC was performed using a rabbit monoclonal anti-HER2 antibody (clone 4B5) and a conventional 3,3'-diaminobenzidine IHC detection. The HER2 & CEN17 BISH signals were visualized using horseradish peroxidase-based silver and alkaline phosphatase-based red detection systems, respectively with a cocktail of 2,4-dinitrophenyl-labeled HER2 and digoxigenin-labeled CEN17 probes. The performance of the gene-protein assay on tissue microarray slides containing 189 randomly selected FFPE clinical breast cancer tissue cores was compared to that of the separate HER2 IHC and HER2 & CEN17 BISH assays.

RESULTS

HER2 protein detection was optimal when the HER2 IHC protocol was used before (rather than after) the BISH protocol. The sequential use of HER2 IHC and HER2 & CEN17 BISH detection steps on FFPE xenograft tumor sections appropriately co-localized the HER2 protein, HER2 gene, and CEN17 signals after mitigating the silver background staining by using a naphthol phosphate-containing hybridization buffer for the hybridization step. The HER2 protein and HER2 gene status obtained using the multiplex HER2 gene-protein assay demonstrated high concordance with those obtained using the separate HER2 IHC and HER2 & CEN17 BISH assays, respectively.

CONCLUSIONS

We have developed a protocol that allows simultaneous visualization of the HER2 IHC and HER2 & CEN17 BISH targets. This automated protocol facilitated the determination of HER2 protein and HER2 gene status in randomly selected breast cancer samples, particularly in cases that were equivocal or exhibited tumor heterogeneity. The HER2 gene-protein assay produced results virtually equivalent to those of the single FDA-approved HER2 IHC and HER2 & CEN17 BISH assays.

VIRTUAL SLIDES

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2041964038705297.

Emerging technologies for assessing HER2 amplification

Patients with human epidermal growth factor receptor-2 (HER2)+ breast cancer are eligible for trastuzumab treatment; therefore, accurate assessment of HER2 status is essential. Until recently, only 2 methods were validated for determining the HER2 status of breast tumors in the routine diagnostic setting: immunohistochemical analysis and fluorescence in situ hybridization (FISH). Recently, bright-field in situ hybridization techniques such as chromogenic in situ hybridization (CISH) and silver-enhanced in situ hybridization (SISH), which combine features of immunohistochemical analysis and FISH, have been introduced for the determination of HER2 status. These new techniques use a peroxidase enzyme-labeled probe with chromogenic detection, instead of a fluorescent-labeled probe, allowing results to be visualized by standard bright-field microscopy. Thus, the histologic features and HER2 status of a specimen can be evaluated in parallel. Moreover, signals do not decay over time. This review discusses recent publications regarding CISH and SISH testing, including results scoring and concordance between FISH and immunohistochemical analysis.

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.

Her-2/neu amplification and breast cancer survival: results from the Shanghai breast cancer study

Her-2/neu is a member of the epidermal growth factor receptor family that has been found to be overexpressed or amplified in approximately 20-30% of breast cancers. Negative prognosticators and a shortened survival have been shown to be associated with these changes in Her-2/neu, but previous studies have consisted of predominantly Caucasian populations. Additionally, chromogenic in situ hybridization (CISH) has been suggested to be a potential alternative to fluorescent in situ hybridization (FISH), the expensive and labor-intensive gold standard assay currently used for Her-2/neu amplification. This study evaluated breast cancer samples from 313 Chinese women participating in the Shanghai breast cancer study, of which 100 (32%) were found to have Her-2/neu amplification by either FISH or CISH methodologies. After a mean follow-up period of 6.67 years, Her-2/neu amplification was found to be significantly associated with an increased hazard of death, regardless of which assay was used to detect amplification. Patients with Her-2/neu amplification were approximately 60% more likely to die of the disease (HR: 1.6, 95% CI: 1.0-2.6) than patients without amplification, even after adjusting for age, stage, menopausal status, chemotherapy, radiotherapy and tamoxifen treatment. Furthermore, the negative prognostic effect of Her-2/neu varied by cancer stage, with greater risks of death evident among later stage patients. This study supports a negative prognostic role for Her-2/neu in breast cancer survival among a Chinese population, irrespective of whether FISH or CISH is used to detect amplification of the Her-2/neu gene.

Prognostic value of HER2 gene amplification detected by chromogenic in situ hybridization (CISH) in metastatic breast cancer

After so many years of research, clinical value of HER2 (Human epidermal growth factor receptor 2) is unclear. Perhaps the main reason is variability of testing methods that produce controversial results. There is a lack of studies regarding prognostic value of CISH especially in metastatic breast cancer (MBC) when risk evaluation is based on different parameters than for primary breast cancer. Aim of this study was to compare prognostic relevance of HER2 status in MBC tested by two different methods i.e. immunohistochemistry (IHC) and chromogenic in situ hybridization (CISH). HER2 status of the same group of 107 MBC patients was determined by IHC (protein overexpression) and by CISH (gene amplification). HER2 results obtained by IHC and CISH showed significant correlation, beside the existence of discrepancies. Beside the significant correlation in two methods, there was a difference in prognostic values of compared methods during the course of metastatic disease. There was a significant difference in progression-free interval (PFI) between HER2 non-amplified and HER2 amplified cases determined by CISH, in postmenopausal subgroup and node-positive subgroup, but no significant difference for IHC stratified MBC patients. CISH seems to be accurate and more informative method than IHC regarding prognostic value of HER2 in metastatic breast cancer.

HER2 evaluation using the novel rabbit monoclonal antibody SP3 and CISH in tissue microarrays of invasive breast carcinomas

BACKGROUND

Laboratory methods for HER2 assessment currently include immunohistochemical (IHC) methods (measuring protein overexpression) and fluorescence in situ hybridisation (FISH) (measuring gene amplification). The measure of HER2 protein by IHC is usually assessed by the mouse monoclonal antibody CB11, and polyclonal antibodies (Herceptest) directed against the internal portion of the receptor. Recently, chromogenic in situ hybridisation (CISH), in which HER2 is detected by a peroxidase reaction and the gene amplification can be determined by regular bright-field microscopy, has emerged as an alternative to FISH.

AIMS

To evaluate the status of HER2 in tissue microarrays (TMAs) of invasive breast cancer using the novel rabbit monoclonal antibody SP3 directed against the external portion of HER2, and correlate the results with CB11 and CISH.

METHODS

IHC was performed with two antibodies (CB11 and SP3) and CISH for HER2 in 10 TMA blocks with 190 formalin-fixed paraffin-embedded cases of invasive breast carcinomas.

RESULTS

The correlation between SP3 and CB11 was significant (p<0.001) with an agreement rate of 86.9%. When the staining pattern of the two antibodies was compared, the majority of SP3 immunostainings were assessed more easily, with a strong complete membrane staining pattern without non-specific cytoplasmic staining. There was a good correlation between SP3 and CISH (p<0.001). 23/24 SP3 3+ cases showed gene amplification, 97.3% of the cases without gene amplification were SP3 negative, and 6/7 SP3 2+ were amplified.

CONCLUSION

The high level of agreement between SP3, a monoclonal antibody that recognises the extracellular domain of the HER2 receptor, and CB11 and CISH, shows that this novel antibody is a reliable candidate to evaluate the expression of HER2 in breast cancer.

Analysis of HER2 by chromogenic in situ hybridization and immunohistochemistry in lymph node-negative breast carcinoma: Prognostic relevance

In patients with lymph node-negative breast carcinoma (LNNBC), the prevalence of HER2 overexpression and gene amplification and their prognostic value have not been extensively evaluated. We examined 162 patients with LNNBC with complete follow-up. Immunohistochemistry (IHC) for HER2, Ki67, and p53 was performed. HER2 gene status was analyzed by chromogenic in situ hybridization (CISH) and discordant cases by fluorescence in situ hybridization. HER2 overexpression was seen in 24.7% of cases (40/162) and amplification by CISH in 17.6% (28/159). Agreement between IHC and CISH was achieved in 147 (92.5%) cases. Amplification was seen in 21 (100%) of 21 (3+), 6 (35.3%) of 17 (2+), and 1 (0.6%) of 121 (0-1+) tumors. Fluorescence in situ hybridization detected 3 (1.8%) additional cases. HER2 overexpression and amplification were present in tumors of high grade, with necrosis and lymph-vascular invasion (LVI) (all P < .027). In addition, amplified tumors showed Ki67 of more than 20% and p53 overexpression (P < .05). By univariate analysis, shorter disease-free survival (DFS) and overall survival (OS) were seen for patients with tumors showing HER2 amplification, LVI, and Ki67 of more than 20% (P < .05) (Kaplan-Meier). However, the multivariate analysis (Cox regression) demonstrated only Ki67 as an independent prognostic factor for both DFS (P = .017) and OS (P = .010), and as a trend for HER2 gene status (OS, P = .087) and LVI (DFS, P = .11; OS, P = .063). We conclude that IHC is a reliable method for detecting HER2 expression that can be complemented by CISH in nondefinitive cases (2+). Moreover, CISH is a valuable tool for the assessment of HER2 gene status with potential prognostic value and, therefore, in clinical decision making for treatment of high-risk LNNBC.

HER-2 Gene Amplification in Paget Disease of the Nipple and Extramammary Site: A Chromogenic In Situ Hybridization Study

Patients with human epidermal growth factor receptor 2 (HER-2) overexpressing breast carcinomas have a more aggressive clinical behavior and their tumors are often hormone receptor negative. However, the recently introduced anti-HER-2 antibody trastuzumab has been proven to improve the survival and controls the disease in a significant proportion of these patients. Therefore, the analysis of HER-2 in patients with breast cancer has become an important and routine test to select those who may benefit from the gene-based targeted therapy trastuzumab (herceptin). There is good correlation between HER-2/neu protein overexpression and HER-2 gene amplification in breast cancer. However, inconsistent results have been reported in the rate of HER-2/neu protein overexpression in other malignant neoplasms. Furthermore, only rare studies have investigated the correlation between the HER-2/neu protein overexpression and the status of HER-2 gene in these tumors. We investigated the HER-2 gene and protein status in several cases of Paget disease of the nipple and vulva by using a chromogenic in situ hybridization assay and immunohistochemistry. We find that the majority of the Paget disease of the breast demonstrate HER-2 gene amplification, whereas most of the extramammary Paget disease lack HER-2 gene amplification. In addition, our results show a good correlation between HER-2/neu protein overexpression and HER-2 gene amplification in Paget disease of the nipple, but we were unable to confirm this correlation in HER-2/neu protein overexpressing Paget disease of the vulva.

Prognostic, predictive and therapeutic implications of HER2 in invasive epithelial ovarian cancer

The HER2 oncogene encodes a transmembrane protein partially homologous to epidermal growth factor receptor. This oncogene has been studied mainly in breast cancer where it has prognostic, predictive and therapeutic target value. The expression of HER2 in epithelial ovarian cancer has been less studied. HER2 expression can be determined through IHC, FISH, CISH and ELISA among other tests, with reported positivity frequencies of overexpression varying from 1.8% to 76%. In some studies HER2 overexpression has been associated with advanced stages, poorly differentiated tumors, resistance to chemotherapy and shortened survival. Although trastuzumab is able to produce a low response rate as a single agent in pretreated ovarian cancer patients with overexpression of HER2, its usefulness is limited due to the low frequency of strong expression. To date there is not enough bases for assessment and HER2-based therapies in epithelial ovarian cancer.

Epidermal growth factor receptor expression and gene amplification in colorectal carcinoma: an immunohistochemical and chromogenic in situ hybridization study

Recent data suggest that detection of epidermal growth factor receptor protein by immunohistochemistry (IHC) does not predict response to the antiepidermal growth factor receptor drug, cetuximab, in patients with colorectal carcinoma. In searching for foundation for further investigation to optimize patient selection for cetuximab therapy, this study sought to exploit the tissue microarray and chromogenic in situ hybridization techniques to evaluate the status of epidermal growth factor receptor gene amplification in colorectal cancer and its relationship with protein expression by IHC. The study included 158 primary or metastatic colorectal adenocarcinomas. Immunohistochemical results were scored as 0-3+ based on the intensity of membrane staining. The in situ hybridization signals were counted in 30 nuclei per tissue core. Overall, the rate of tissue loss was 7%, yielding 147 analyzable cases: 123 primary, 24 metastatic. Positive immunohistochemical staining of any intensity was detected in 85% (105/123) of primary and 79% (19/24) of metastatic tumors, whereas gene amplification (>5 gene copies/nucleus) was only seen in 12% (15/123) of primary and 8% (2/24) of metastatic tumors. Only 2/15 primary and 1/2 metastatic tumors that showed gene amplification were amplified at a high level (>10 gene copies/nucleus). Although a positive correlation was detected between the intensity of protein expression and the likelihood of gene amplification in both the primary (P = 0.01) and the metastatic (P = 0.05) tumors, IHC had a low specificity (17% in primary, 23% in metastatic) in predicting gene amplification. Conversely, all tumors that did not express the protein by IHC lacked gene amplification. Thus, this study shows that only a small fraction of epidermal growth factor receptor- positive colorectal carcinomas detected by IHC are associated with gene amplification. Additional studies are needed to determine whether epidermal growth factor receptor gene amplification bears any informative value in predicting response to cetuximab-based therapy.

Comparison between immunohistochemistry and chromogenic in situ hybridization in assessing HER-2 status in breast cancer

Human epidermal growth factor receptor-2 (HER-2) is usually determined as a potential target for breast cancer therapy. The purpose of the present study was to compare chromogenic in situ hybridization (CISH) with immunohistochemistry (IHC) in determination of HER-2 status, in metastatic breast cancer patients screened for the clinical study of chemotherapy +/- herceptin. It was possible to assess both CISH and IHC in 56 cases, using CISH Detection Kit (Zymed) and HercepTest (DakoCytomation), respectively. HER-2 was amplified by CISH in 32 cases (57%) while 33 (59%) were HER-2-positive by IHC. A concordance between HER-2 status determined by CISH and IHC was noted in 43 of 56 cases (77%; P = 0.00008). Gene amplification was observed in 6/16 cases (37.5%) in IHC-negative subgroup (1+), while no amplification was observed in 5/10 cases (50%) in the IHC-positive subgroup (2+). These results suggest that there was a greater heterogeneity on the genetic level and that simple IHC classification was not sufficient. It is suggested that CISH could be considered as a useful additional method to IHC in determining HER-2 status in breast cancer patients, with a recommendation for testing not only the 2+ but also the 1+ subgroup of patients.