Trastuzumab as adjuvant therapy for early breast cancer: the importance of accurate human epidermal growth factor receptor 2 testing

In ER-Positive, HER2-Negative Breast Cancers, HER2 mRNA Levels Correlate Better with Clinicopathologic Features and Oncotype DX Recurrence Score than HER2 Immunohistochemistry

With the approval of trastuzumab deruxtecan for treating advanced human epidermal growth factor receptor-2 (HER2) low breast cancer (BC), it has become increasingly important to develop more accurate and reliable methods to identify HER2-low BC. In addition, HER2 immunohistochemistry (IHC) has limitations for quantification of HER2. We explored the relationship between HER2 IHC and mRNA levels and evaluated whether HER2 IHC scores and mRNA levels are associated with clinicopathologic features and Oncotype DX Recurrence Score (RS) in estrogen receptor (ER)-positive, HER2-negative BCs. A total of 750 BCs sent for Oncotype DX (ODX) testing were included in this study, and 559 with HER2 mRNA levels were available. There were no statistically significant differences between HER2 0 and HER2-low BC in clinicopathologic variables or ODX RS using HER2 IHC. There was a significant difference in median HER2 mRNA values between HER2 0 and HER2-low (8.7 vs 9.3, P < .001); however, the HER2 mRNA distribution had substantial overlap between these 2 groups with a suboptimal area under the receiver operating characteristic curve (area under the receiver operating characteristic curve = 0.68). A HER2 mRNA value of 9.2 was generated as the optimal cutoff for distinguishing HER2 0 and HER2-low BC. Comparing ER+ BCs with HER2 mRNA high (>9.2) and low (≤9.2) revealed a statistically significant difference in most clinicopathologic variables and ODX RS. From this large cohort of ER-positive, HER2-negative BC, our results demonstrated that HER2 mRNA levels correlated better with clinicopathologic features and recurrence risk as assessed by ODX RS than HER2 IHC scores. Our findings suggest that HER2 mRNA-detecting methods could potentially serve as a quantitative and reliable method for identifying a biologically meaningful group of HER2-low BC. Further study is needed to determine whether HER2 mRNA levels could be more reliable than IHC for identifying which patients will be most likely to benefit from trastuzumab deruxtecan.

Concordance of the 21-gene assay between core needle biopsy and resection specimens in early breast cancer patients

BACKGROUND

Adjuvant therapy decisions may be partly based on the results of a multigene quantitative reverse transcription-polymerase chain reaction (RT-PCR)-based assay: the 21-gene recurrence score (RS) test of resection specimens. When necessary, core needle biopsy (CNB) may be considered as a surrogate. Here, we evaluated the concordance in gene expression according to results from RT-PCR-based RS testing between paired CNBs and resection specimens.

METHODS

CNBs and resection specimens from 50 breast cancer (BC) patients were tested to calculate RSs. First, we examined the concordance of the ER, PR and HER-2 status of tissue samples indicated by immunohistochemical (IHC) and RT-PCR analyses. Then, we compared the IHC findings of ER, PR, HER-2 and Ki-67 staining across paired samples. Ultimately, the RS and single-gene results for ER, PR, HER-2 and Ki-67 were explored between paired samples.

RESULTS

The concordance between IHC and RT-PCR was 100%, 80.0% and 100% for ER, PR and HER-2, respectively, in both resection specimens and CNBs. The concordance for IHC ER, PR, HER-2 and Ki-67 status was 100%, 94.0%, 52.0% and 82.0%, respectively, between paired samples. RS results from paired samples showed a strong correlation. The overall concordance in RS group classification between samples was 74%, 72% and 78% based on traditional cutoffs, TAILORx cutoffs and ASCO guidelines, respectively. ER, PR, HER-2 and Ki-67 were modestly- to- strongly correlated between paired samples according to the RT-PCR results.

CONCLUSION

A modest- to- strong correlation of ER, PR, HER-2 and Ki-67 gene expression and RS between CNBs and resection specimens was observed in the present study. The 21-gene RS test could be reliably performed on CNBs. ER, PR and HER-2 status showed remarkable concordance between the IHC and RT-PCR analyses. The concordance between paired samples was high for the IHC ER, PR and Ki-67 results and low for HER-2.

Impact of Specimen Type and Specimen Number on HER2 Status in Gastroesophageal Junction and Gastric Adenocarcinoma

OBJECTIVES

Human epidermal growth factor receptor 2 (HER2) is expressed in some gastric and gastroesophageal junction adenocarcinomas. There were two goals: assess the impact of specimen type on HER2 status and evaluate HER2 concordance with multiple specimens.

METHODS

All cases were evaluated by immunohistochemistry (IHC) for HER2 and interpreted using established criteria. Fluorescence in situ hybridization (FISH) was performed on a subset.

RESULTS

Of 460 specimens, 83.9% were IHC negative, 5.4% were equivocal, and 10.7% were IHC positive. Of those with FISH testing, 78.5% were FISH negative, and 21.5% were FISH positive. IHC-FISH concordance for biopsy specimens, resections, and metastases was 82%, 84%, and 86%, respectively. With one vs two vs three or more specimens, the HER2-positive rate increased from 10.5% to 18.1% to 24.1%, respectively.

CONCLUSIONS

HER2 testing may be performed on biopsy specimens with a relatively high concordance rate with resection specimens, and if multiple samples are analyzed from a single patient, the HER2-positive rate increases over twofold.

Activation of LncRNA TINCR by H3K27 acetylation promotes Trastuzumab resistance and epithelial-mesenchymal transition by targeting MicroRNA-125b in breast Cancer

BACKGROUND

Trastuzumab resistance followed by metastasis is a major obstacle for improving the clinical outcome of patients with advanced human epidermal growth factor receptor 2-positive (HER-2+) breast cancer. While long non-coding RNAs (lncRNAs) can modulate cell behavior, the contribution of these RNAs in trastuzumab resistance and metastasis of HER-2+ breast cancer is not well known. In this study, we sought to identify the regulatory role of lncRNA in trastuzumab resistance and accompanied Epithelial-mesenchymal Transition (EMT) process in advanced HER-2+ breast cancer.

METHODS

Trastuzumab-resistant SKBR-3-TR and BT474-TR cell lines were established by grafting SKBR-3 and BT474 cells into mouse models and subjected to trastuzumab treatment. LncRNA microarray followed by quantitative reverse transcription PCR (qRT-PCR) was carried out to verify the differentially expressed lncRNAs. Western blotting, bioinformatics analysis, immunofluorescence assay and immunoprecipitation assays (ChIP and RIP) were performed to identify the involvement and functional interactions between H3K27 acetylation and terminal differentiation-induced non-coding RNA (TINCR) or between TINCR and its downstream genes including miR-125b, HER-2 and Snail-1. In addition, a series of in vitro and in vivo assays were performed to assess the functions of TINCR.

RESULTS

An increase in both, IC₅₀ value of trastuzumab and EMT was observed in the established trastuzumab-resistant cell lines. The expression level of TINCR was significantly increased in trastuzumab-resistant cells when compared with sensitive cells. Knockdown of TINCR reversed the trastuzumab resistance and the acquired EMT in these cells. TINCR was detected in the cytoplasm of breast cancer cells and could sponge miR-125b, thereby releasing HER-2 and inducing trastuzumab resistance. In addition, Snail-1 was found to be the target gene of miR-125b and overexpression of Snail-1 could reverse the suppressed migration, invasion, and EMT caused by TINCR silencing. The upregulation of TINCR in breast cancer was attributed to the CREB-binding protein (CBP)-mediated H3K27 acetylation at the promoter region of TINCR. Clinically, HER-2+ breast cancer patients with high TINCR expression levels were associated with poor response to trastuzumab therapy and shorter survival time.

CONCLUSION

TINCR could promote trastuzumab resistance and the accompanied EMT process in breast cancer. Therefore, TINCR might be a potential indicator for prognosis and a therapeutic target to enhance the clinical efficacy of trastuzumab treatment.

A novel detection methodology for HER2 protein quantitation in formalin-fixed, paraffin embedded clinical samples using fluorescent nanoparticles: an analytical and clinical validation study

BACKGROUND

Clinical assays for the assessment of the human epidermal growth factor receptor-2 (HER2) status in breast cancer include immunohistochemistry (IHC) and in situ hybridization (ISH), both of which have limitations. Recent studies have suggested that a more quantitative approach to the measurement of HER2 protein expression may improve specificity in selecting patients for HER-2 targeted therapy. In the current study, we have used HER2 expression in breast cancer cell lines and clinical samples as a model to explore the potential utility of a novel immunodetection technique, using streptavidin coated Phosphor Integrated Dot fluorescent nanoparticles (PID), which can be quantitatively measured using computer analysis.

METHODS

The expression of HER2 protein in cell lines was evaluated with antibody-binding capacity using fluorescence-activated cell sorting (FACS) for comparison with PID measurements to test for correlations with existing quantitative protein analysis methodologies. Various other analytic validation tests were also performed, including accuracy, precision, sensitivity, robustness and reproducibility. A methods comparison study investigated correlations between PID versus IHC and ISH in clinical samples. Lastly, we measured HER2 protein expression using PID in the pretreatment biopsies from 34 HER2-positive carcinomas that had undergone neoadjuvant trastuzumab-based chemotherapy.

RESULTS

In the analytic validation, PID HER2 measurements showed a strong linear correlation with FACS analysis in breast cell lines, and demonstrated significant correlations with all aspects of precision, sensitivity, robustness and reproducibility. PID also showed strong correlations with conventional HER2 testing methodologies (IHC and ISH). In the neoadjuvant study, patients with a pathologic complete response (pCR) had a significantly higher PID score compared with patients who did not achieve a pCR (p = 0.011), and was significantly correlated to residual cancer burden (RCB) class (p = 0.026, R² = 0.9975).

CONCLUSIONS

Analytic testing of PID showed that it may be a viable testing methodology that could offer advantages over other experimental or conventional biomarker diagnostic methodologies. Our data also suggests that PID quantitation of HER2 protein may offer an improvement over conventional HER2 testing in the selection of patients who will be the most likely to benefit from HER2-targeted therapy. Further studies with a larger cohort are warranted.

Melatonin regulates tumor aggressiveness under acidosis condition in breast cancer cell lines

Breast cancer progression is composed of multiple steps that are influenced by tumor cell adaptations to survive under acidic conditions in the tumor microenvironment. Regulation of this cell survival behavior is a promising strategy to avoid cancer development. Melatonin is a natural hormone produced and secreted by the pineal gland capable of modulating different biological pathways in cancer. Although the anti-cancer effects of melatonin are currently widespread, its role in the acid tumor microenvironment remains poorly understood. The aim of the present study was to investigate the effect of low pH (6.7) on human breast cancer cell lines MCF-7 and MDA-MB-231, and the effectiveness of melatonin in acute acidosis survival mechanisms. Cell viability was measured by a MTT assay and the protein expression of glucose transporter (GLUT)-1, Ki-67 and caspase-3 was evaluated by immunocytochemical (ICC) analysis following low pH media and melatonin treatment. In both cell lines the viability was decreased after melatonin treatment (1 mM) under acidosis conditions for 24 h. ICC analysis showed a significant increase in GLUT-1 and Ki-67 expression at pH 6.7, and a decrease after treatment with melatonin for 12 and 24 h. The low pH media decreased the expression of caspase-3, which was increased after melatonin treatment for 12 and 24 h. Overall, the results of the present study revealed melatonin treatment increases apoptosis, as indicated by changes in caspase-3, and decreases proliferation, indicated by changes to Ki-67, and GLUT-1 protein expression under acute acidosis conditions in breast cancer cell lines.

Pan-HER-targeted approach for cancer therapy: Mechanisms, recent advances and clinical prospect

The Human Epidermal Growth Factor Receptor family is composed of 4 structurally related receptor tyrosine kinases that are involved in many human cancers. The efficacy and safety of HER inhibitors have been compared in a wide range of clinical trials, suggesting the superior inhibitory ability of multiple- HER-targeting blockade compared with single receptor antagonists. However, many patients are currently resistant to current therapeutic treatment and novel strategies are warranted to conquer the resistance. Thus, we performed a critical review to summarize the molecular involvement of HER family receptors in tumour progression, recent anti-HER drug development based on clinical trials, and the potential resistance mechanisms of anti-HER therapy.

Using the Modified Magee Equation to Identify Patients Unlikely to Benefit From the 21-Gene Recurrence Score Assay (Oncotype DX Assay)

OBJECTIVES

This study aimed to compare a modified Magee equation with Oncotype DX (Genomic Health, Redwood City, CA) recurrence score (RS) and identify patients who are unlikely to benefit from Oncotype DX.

METHODS

Magee equation RS was calculated in 438 cases and correlated with Oncotype DX RS.

RESULTS

The Pearson correlation coefficient ( r ) for the Magee equation and Oncotype DX RS was 0.6645 ( P  < .00001), and the overall agreement was 66.4%. All cases (11.6%) with a Magee equation RS greater than 30 or 11 or less had been correctly predicted to have either high Oncotype DX RS or low Oncotype DX RS, respectively.

CONCLUSIONS

The modified Magee equation is able to identify up to 12% patients who are unlikely to benefit from Oncotype DX testing. Using the modified Magee equation RS on these patients would be an alternative to Oncotype DX, leading to cost savings.

Automated Image Analysis of HER2 Fluorescence In Situ Hybridization to Refine Definitions of Genetic Heterogeneity in Breast Cancer Tissue

Human epidermal growth factor receptor 2 gene- (HER2-) targeted therapy for breast cancer relies primarily on HER2 overexpression established by immunohistochemistry (IHC) with borderline cases being further tested for amplification by fluorescence in situ hybridization (FISH). Manual interpretation of HER2 FISH is based on a limited number of cells and rather complex definitions of equivocal, polysomic, and genetically heterogeneous (GH) cases. Image analysis (IA) can extract high-capacity data and potentially improve HER2 testing in borderline cases. We investigated statistically derived indicators of HER2 heterogeneity in HER2 FISH data obtained by automated IA of 50 IHC borderline (2+) cases of invasive ductal breast carcinoma. Overall, IA significantly underestimated the conventional HER2, CEP17 counts, and HER2/CEP17 ratio; however, it collected more amplified cells in some cases below the lower limit of GH definition by manual procedure. Indicators for amplification, polysomy, and bimodality were extracted by factor analysis and allowed clustering of the tumors into amplified, nonamplified, and equivocal/polysomy categories. The bimodality indicator provided independent cell diversity characteristics for all clusters. Tumors classified as bimodal only partially coincided with the conventional GH heterogeneity category. We conclude that automated high-capacity nonselective tumor cell assay can generate evidence-based HER2 intratumor heterogeneity indicators to refine GH definitions.

Omics approaches to individual variation: modeling networks and the virtual patient

Every human is unique. We differ in our genomes, environment, behavior, disease history, and past and current medical treatment—a complex catalog of differences that often leads to variations in the way each of us responds to a particular therapy. We argue here that true personalization of drug therapies will rely on “virtual patient” models based on a detailed characterization of the individual patient by molecular, imaging, and sensor techniques. The models will be based, wherever possible, on the molecular mechanisms of disease processes and drug action but can also expand to hybrid models including statistics/machine learning/artificial intelligence-based elements trained on available data to address therapeutic areas or therapies for which insufficient information on mechanisms is available. Depending on the disease, its mechanisms, and the therapy, virtual patient models can be implemented at a fairly high level of abstraction, with molecular models representing cells, cell types, or organs relevant to the clinical question, interacting not only with each other but also the environment. In the future, “virtual patient/in-silico self” models may not only become a central element of our health care system, reducing otherwise unavoidable mistakes and unnecessary costs, but also act as “guardian angels” accompanying us through life to protect us against dangers and to help us to deal intelligently with our own health and wellness.

miR-155 downregulates ErbB2 and suppresses ErbB2-induced malignant transformation of breast epithelial cells

ErbB2 is a vital breast cancer gene and its overexpression has a decisive role in breast tumor initiation and malignant progression. However, the molecular mechanisms that underlie ErbB2 dysregulation in breast cancer cells remain incompletely understood. In this study, we found that ErbB2 expression is inversely correlated with the level of miR-155, a well-documented oncogenic miRNA, in ErbB2-positive breast tumors. We further determined that miR-155 potently suppresses ErbB2 in breast cancer cells. Mechanistically, miR-155 acts to downregulate ErbB2 via two distinct mechanisms. First, miR-155 represses ErbB2 transcription by targeting HDAC2, a transcriptional activator of ErbB2. Second, miR-155 directly targets ErbB2 via a regulatory element in its coding region. Intriguingly, miR-155 is upregulated by trastuzumab and in turn leads to a reduction of ErbB2 expression in trastuzumab-treated ErbB2-positive breast cancer cells. Functional studies showed that miR-155 inhibits ErbB2-induced malignant transformation of human breast epithelial cells. Thus, our findings reveal an intriguing miR-155-ErbB2 context in regulating the malignant transformation of breast epithelial cells, and thereby indicate a novel mode of action for miR-155 in ErbB2-positive breast cancer.

HER2 FISH classification of equivocal HER2 IHC breast cancers with use of the 2013 ASCO/CAP practice guideline

The status of human epidermal growth factor receptor 2 (HER2, ERBB2) determines the eligibility of breast cancer patients to receive HER2-targeted therapy. The majority of HER2 testing in the U.S. is performed using a combination of immunohistochemistry (IHC) screening followed by fluorescence in situ hybridization (FISH) for IHC equivocal cases. In 2013, the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) updated the guideline for HER2 testing. This study evaluates the impact of the 2013 ASCO/CAP updated guideline on final HER2 FISH classification of breast cancers with an equivocal IHC result. For each case, we reported a FISH result according to the 2013 updated guideline and recorded a separated result using the 2007 guideline for investigational purpose. McNemar's test and Bowker's symmetry test were used to compare the classifications by the two guidelines. Among 172 HER2 IHC 2+ equivocal cases, use of the 2103 guideline changed classifications in 36 cases (21 %) when compared with the results expected by use of the 2007 guideline, and yielded a higher proportion of positive (28.5 vs. 23.3 %) and equivocal (16.3 vs. 4.1 %), and a lower proportion of negative (55.2 vs. 72.7 %) cases (p < 0.001). The major classification change with use of the updated guideline is from the HER2 FISH negative to equivocal in 26 cases (15 %). Our study has shown that implementation of the 2013 ASCO/CAP updated guideline has significant impact on HER2 classification for breast cancers with an equivocal HER2 IHC result and therefore increased the use of HER2-targeted therapy. Our data have also shown that reflex FISH is effective for final classification of the IHC equivocal cases and that polysomy 17 (CEP17 copy number ≥3/cell) is present in a significantly higher proportion of cases with an equivocal HER2 FISH classification.

Use of modified Magee equations and histologic criteria to predict the Oncotype DX recurrence score

Oncotype DX (Genomic Health, Redwood City, CA, USA, current list price $4,350.00) is a multigene quantitative reverse transcription-polymerase chain reaction-based assay that estimates the risk of distant recurrence and predicts chemotherapy benefit for patients with estrogen receptor (ER)-positive breast cancers. Studies have suggested that standard histologic variables can provide similar information. Klein and Dabbs et al have shown that Oncotype DX recurrence scores can be estimated by incorporating standard histologic variables into equations (Magee equations). Using a simple modification of the Magee equation, we predict the Oncotype DX recurrence score in an independent set of 283 cases. The Pearson correlation coefficient (r) for the Oncotype DX and average modified Magee recurrence scores was 0.6644 (n=283; P<0.0001). 100% of cases with an average modified Magee recurrence score>30 (n=8) or an average modified Magee recurrence score<9 (with an available Ki-67, n=5) would have been correctly predicted to have a high or low Oncotype DX recurrence score, respectively. 86% (38/44) of cases with an average modified Magee recurrence score≤12, and 89% (34/38) of low grade tumors (NS<6) with an ER and PR≥150, and a Ki-67<10%, would have been correctly predicted to have a low Oncotype DX recurrence score. Using an algorithmic approach to eliminate high and low risk cases, between 5% and 23% of cases would potentially not have been sent by our institution for Oncotype DX testing, creating a potential cost savings between $56,550.00 and $282,750.00. The modified Magee recurrence score along with histologic criteria may be a cost-effective alternative to the Oncotype DX in risk stratifying certain breast cancer patients. The information needed is already generated by many pathology laboratories during the initial assessment of primary breast cancer, and the equations are free.

Oncogenic alterations in ERBB2/HER2 represent potential therapeutic targets across tumors from diverse anatomic sites of origin

BACKGROUND

Targeted ERBB2/HER2 inhibitors are approved by the U.S. Food and Drug Administration for the treatment of breast, gastric, and esophageal cancers that overexpress or amplify HER2/ERBB2, as measured by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), respectively. Activating mutations in ERBB2 have also been reported and are predicted to confer sensitivity to these targeted agents. Testing for these mutations is not performed routinely, and FISH and IHC are not applied outside of these approved indications.

MATERIALS AND METHODS

We explored the spectrum of activating ERBB2 alterations across a collection of ∼ 7,300 solid tumor specimens that underwent comprehensive genomic profiling using next-generation sequencing. Results were analyzed for base substitutions, insertions and deletions, select rearrangements, and copy number changes.

RESULTS

Known oncogenic ERBB2 alterations were identified in tumors derived from 27 tissues, and ERBB2 amplification in breast, gastric, and gastroesophageal cancers accounted for only 30% of these alterations. Activating mutations in ERBB2 were identified in 131 samples (32.5%); amplification was observed in 246 samples (61%). Two samples (0.5%) harbored an ERBB2 rearrangement. Ten samples (2.5%) harbored multiple ERBB2 mutations, yet mutations and amplifications were mutually exclusive in 91% of mutated cases.

CONCLUSION

Standard slide-based tests for overexpression or amplification of ERBB2 would fail to detect the majority of activating mutations that occur overwhelmingly in the absence of copy number changes. Compared with current clinical standards, comprehensive genomic profiling of a more diverse set of tumor types may identify ∼ 3.5 times the number of patients who may benefit from ERBB2-targeted therapy.

Oncogenic alterations in ERBB2/HER2 represent potential therapeutic targets across tumors from diverse anatomic sites of origin

BACKGROUND

Targeted ERBB2/HER2 inhibitors are approved by the U.S. Food and Drug Administration for the treatment of breast, gastric, and esophageal cancers that overexpress or amplify HER2/ERBB2, as measured by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), respectively. Activating mutations in ERBB2 have also been reported and are predicted to confer sensitivity to these targeted agents. Testing for these mutations is not performed routinely, and FISH and IHC are not applied outside of these approved indications.

MATERIALS AND METHODS

We explored the spectrum of activating ERBB2 alterations across a collection of ∼ 7,300 solid tumor specimens that underwent comprehensive genomic profiling using next-generation sequencing. Results were analyzed for base substitutions, insertions and deletions, select rearrangements, and copy number changes.

RESULTS

Known oncogenic ERBB2 alterations were identified in tumors derived from 27 tissues, and ERBB2 amplification in breast, gastric, and gastroesophageal cancers accounted for only 30% of these alterations. Activating mutations in ERBB2 were identified in 131 samples (32.5%); amplification was observed in 246 samples (61%). Two samples (0.5%) harbored an ERBB2 rearrangement. Ten samples (2.5%) harbored multiple ERBB2 mutations, yet mutations and amplifications were mutually exclusive in 91% of mutated cases.

CONCLUSION

Standard slide-based tests for overexpression or amplification of ERBB2 would fail to detect the majority of activating mutations that occur overwhelmingly in the absence of copy number changes. Compared with current clinical standards, comprehensive genomic profiling of a more diverse set of tumor types may identify ∼ 3.5 times the number of patients who may benefit from ERBB2-targeted therapy.

Pathologic diagnosis, immunohistochemistry, multigene assays and breast cancer treatment: progress toward "precision" cancer therapy

Clinical decisions regarding the suitability of adjuvant systemic therapy for individual patients with breast cancer depends on comprehensive assessment of the underlying biology of each patient's tumor. The previous clinical-pathologic paradigm for treatment, which had been used for decades, now has been augmented by significant advances in molecular analysis of breast tumor tissue samples. Molecular testing has the potential to understand better both tumor biology and clinical behavior, which enables more appropriate therapy choices to be made. We review the rapid evolution in profiling breast cancer tissues, and discuss the current evidence for clinical use of this information and how the emerging molecular paradigm can be integrated into the clinical-pathologic context as we progress toward "precision" therapy for patients with breast cancer and other solid tumors.

Herceptin resistance database for understanding mechanism of resistance in breast cancer patients

Monoclonal antibody Trastuzumab/Herceptin is considered as frontline therapy for Her2-positive breast cancer patients. However, it is not effective against several patients due to acquired or de novo resistance. In last one decade, several assays have been performed to understand the mechanism of Herceptin resistance with/without supplementary drugs. This manuscript describes a database HerceptinR, developed for understanding the mechanism of resistance at genetic level. HerceptinR maintains information about 2500 assays performed against various breast cancer cell lines (BCCs), for improving sensitivity of Herceptin with or without supplementary drugs. In order to understand Herceptin resistance at genetic level, we integrated genomic data of BCCs that include expression, mutations and copy number variations in different cell lines. HerceptinR will play a vital role in i) designing biomarkers to identify patients eligible for Herceptin treatment and ii) identification of appropriate supplementary drug for a particular patient. HerceptinR is available at http://crdd.osdd.net/raghava/herceptinr/.

Immunohistochemical investigation of the angiogenic proteins VEGF, HIF-1α and CD34 in invasive ductal carcinoma of the breast

The expression of prognostic markers in cancer has become important in diagnostic routine and research. A high mitotic rate compromises the individual cell access to oxygen and nutrients, due to reduced blood supply. Cells undertake adaptive measures such as vascular endothelial growth factor (VEGF), expressed under the control of hypoxia-inducible factor-1α (HIF-1α). CD34 is an endothelial marker which can show the presence and distribution of blood vessels. This study evaluated the presence and relative expression of VEGF, HIF-1α and CD34 using immunohistochemistry of 60 breast tumors and double staining, correlating the findings with clinical and pathological variables. High VEGF expression was correlated with low cell proliferation, lymph node-negative, smaller tumor size and patients not receiving hormone therapy. High HIF-1α expression predominated in younger (<50-year) patients, subjected to neo-adjuvant therapy and in p53-negative tumors. Absence of metastasis, radiotherapy or hormone treatment, and estrogen receptor (ER)-positive tumors showed high CD34 immunoreactivity. We suggest that the angiogenic factors VEGF, HIF-1α and CD34 are important in breast cancer progression and their abundance in breast tumors has prognostic and predictive value.

Glutathione and glutathione peroxidase expression in breast cancer: an immunohistochemical and molecular study

The use of prognostic markers for breast cancer allows therapeutic strategies to be defined more efficiently. The expression of glutathione (GSH) and glutathione peroxidase (GPX) in tumor cells has been evaluated as a predictor of prognosis and response to cytotoxic treatments. Its immunoexpression was assessed in 63 women diagnosed with invasive ductal carcinoma in a retrospective study. The results showed that high GSH expression was associated with tumors negative for the estrogen receptor (ER) (P<0.05), and GPX expression was associated with tumors negative for the progesterone receptor (PR) and patient mortality. Focusing on the 37 patients who received adjuvant chemotherapy/radiotherapy (Group I), high expression of GPX was associated with a high rate of patient mortality (P<0.05). The 19 patients who received only adjuvant chemotherapy (Group II) showed high expression of GSH in relation to metastasis (P<0.05). In addition, high levels of GPX expression were significantly associated with a shorter overall survival (P<0.05). To confirm this, the expression of precursor genes of GSH [glutamate cysteine ligase (GCLC) and glutathione synthetase (GSS)] and the GPX gene was analyzed using quantitative PCR in cultured neoplastic mammary cells treated with doxorubicin. Doxorubicin treatment was able to eliminate tumor cells without alterations in the gene expression of GSS, but led to underexpression of the GCLC and GPX genes. Our results suggest that high levels of GPX may be related to the development of resistance to chemotherapy in these tumors, response to treatment and the clinical course of the breast cancer patients.

Multiple protein analysis of formalin-fixed and paraffin-embedded tissue samples with reverse phase protein arrays

Reverse-phase protein arrays (RPPAs) have become an important tool for the sensitive and high-throughput detection of proteins from minute amounts of lysates from cell lines and cryopreserved tissue. The current standard method for tissue preservation in almost all hospitals worldwide is formalin fixation and paraffin embedding, and it would be highly desirable if RPPA could also be applied to formalin-fixed and paraffin embedded (FFPE) tissue. We investigated whether the analysis of FFPE tissue lysates with RPPA would result in biologically meaningful data in two independent studies. In the first study on breast cancer samples, we assessed whether a human epidermal growth factor receptor (HER) 2 score based on immunohistochemistry (IHC) could be reproduced with RPPA. The results showed very good concordance between the IHC and RPPA classifications of HER2 expression. In the second study, we profiled FFPE tumor specimens from patients with adenocarcinoma and squamous cell carcinoma in order to find new markers for differentiating these two subtypes of non-small cell lung cancer. p21-activated kinase 2 could be identified as a new differentiation marker for squamous cell carcinoma. Overall, the results demonstrate the technical feasibility and the merits of RPPA for protein expression profiling in FFPE tissue lysates.

Improving treatment of HER2-positive cancers: opportunities and challenges

Amplification of the ERBB2 gene, which encodes human epidermal growth factor receptor 2 (HER2), causes the overexpression of a major proliferative driver for a subset of breast and gastric cancers. Treatments for patients with HER2-positive cancer include the monoclonal antibody trastuzumab and, in the case of metastatic breast cancer, the tyrosine kinase inhibitor lapatinib. Despite significant improvement in patient outcome as a result of these therapies, challenges remain. This Review focuses on proposed mechanisms of action and resistance in the context of potential new therapeutic options. Therapeutic approaches currently in development likely will yield additional clinically meaningful improvements for patients with HER2-positive cancer.

Glutathione transferase pi (GSTpi) expression in breast cancer: an immunohistochemical and molecular study

Breast cancer is the most frequent cancer in women worldwide. Prognostic markers are important for diagnosis, allowing therapeutic strategies to be defined more efficiently. The expression of the glutathione S-transferase pi isoenzyme (GSTpi) in tumor cells has been evaluated as a predictor of prognosis and in response to cytotoxic treatments. Its immunoexpression was assessed in 63 women diagnosed with invasive ductal carcinoma in a retrospective study. The results were statistically correlated with clinicopathological parameters of patients. The results showed that high GSTpi expression was related to p53-positive tumors, grade III histology, large tumor size and death (p<0.05). The 37 patients who received adjuvant treatment, checked separately, showed high expression of GSTpi in relation to local recurrence, metastasis and death (p<0.05). In addition, high levels of GSTpi expression were significantly associated with a shorter overall survival (p<0.05). To confirm this suspicion, GSTpi gene expression was checked by Real-time PCR in neoplastic mammary cells cultured and subjected to treatment with doxorubicin. Our results suggest that high levels of GSTpi may be related to the development of resistance to chemotherapy in these tumors, the response of these tumors to treatment and the clinical course of the patients involved.

HER2 testing in gastric and gastroesophageal junction cancers: a new therapeutic target and diagnostic challenge

Adenocarcinomas of the stomach and gastroesophageal junction represent a major cause of cancer morbidity and mortality world wide. Complete surgical resection is the mainstay of treatment for nonmetastatic disease; however, many patients are not diagnosed until their disease is either locally advanced or metastatic and therefore unresectable. Clearly, there is an unmet clinical need for new therapeutic strategies, treatment options, and novel therapeutic targets. In a recent trial (Trastuzumab for GAstric cancer), patients assigned to the trastuzumab treatment protocol showed an improved overall survival over those not receiving treatment. Trastuzumab has recently been approved for treatment of advanced gastric and gastroesophageal junction cancers. Pathologists and diagnostic laboratories must be prepared for this new category of specimens requiring human epidermal growth factor receptor 2 testing, and have an awareness of the interpretive differences between breast and gastric cancers.

The challenge and importance of standardizing pre-analytical variables in surgical pathology specimens for clinical care and translational research

The introduction of targeted cancer therapies into clinical practice, in which patients are selected for novel treatments based on results of companion molecular testing of their tumor specimens, has created significant new challenges for the surgical pathology laboratory. These include standardization of tissue handling and sample preparation with accurate documentation to ensure optimal quality of clinical samples to reduce the risk of errors in molecular biology tests. The assay of tumor tissues for biomarkers that can provide predictive data for prognosis or treatment should enable selection of the most appropriate therapies (Yaziji et al. 2008, Hicks and Kulkarni 2008). Major advances have been made in the ability to profile clinical samples for research at the DNA, RNA and protein levels. To translate this new information into the clinical setting, however, the quality of the starting material, in this case the tumor tissue, determines the accuracy and reliability of companion diagnostic assay results and therefore optimal therapeutic strategies. Inaccurate results owing to compromised tissue quality can lead to false positive or false negative results with therapeutic consequences that can harm patients and affect their eventual outcome.

Nitric oxide synthases, cyclooxygenase-2, nitrotyrosine, and angiogenesis in chondrosarcoma and their relation to prognosis

BACKGROUND

The localization in tumor tissue of various markers by immunohistochemistry can help to establish a diagnosis or predict prognosis. Nitric oxide is associated with tumors and has been studied indirectly by nitrotyrosine analysis and with use of the enzymes nitric oxide synthase (NOS)1, NOS2, and NOS3. Nitric oxide reacts with superoxide anions to yield peroxynitrite, which has toxic effects on genes. Peroxynitrite adds a nitro group to the benzene ring of tyrosine to form nitrotyrosine. The accumulation of nitrotyrosine, a stable product in cells, indicates the formation of peroxynitrite. Nitric oxide stimulates the production of cyclooxygenase-2 (COX-2), which has been associated with angiogenesis in tumors. Neovascularization influences tumor prognosis, as demonstrated by microvessel studies with use of CD34, an immunohistochemical endothelial cell marker. This study examines the expression of these markers in chondrosarcomas and their relation to histological grade and prognosis.

METHODS

Tissue microarrays composed of formalin-fixed tissue samples from 101 patients with chondrosarcoma were immunohistochemically stained to localize NOS1, NOS2, NOS3, COX-2, nitrotyrosine, and CD34. Five samples of normal cartilage were used as controls. Patient demographics, selected surgical variables, and tumor grade were tabulated, and the associations were analyzed. Analyses of local and overall survival rates were performed with use of the Kaplan-Meier method, and multivariable analyses were performed.

RESULTS

There was a significant association of nitrotyrosine, COX-2, and CD34 with histological grades (p = 0.022, p = 0.014, and p = 0.028, respectively), but not with overall prognosis (p = 0.064, p = 0.143, and p = 0.581, respectively). The presence of NOS2 was associated with a lower rate of local disease-free survival (p = 0.038), and positive expressions of NOS1 and NOS2 were associated with decreased overall survival rates (p = 0.007 and p < 0.001, respectively). On multivariable analysis, NOS2 expression demonstrated an independent prognostic impact on local disease-free survival; NOS1 and NOS2 expression was a dependent variable, and their isolated or combined expression was related to lower overall survival rates (p = 0.046 and p = 0.004) (hazard ratio, 3.17 [95% confidence interval, 1.0 to 9.8] and 5.58 [95% confidence interval, 1.7 to 18.0], respectively).

CONCLUSIONS

Immunohistochemical markers may have an independent value in predicting the prognosis for patients with chondrosarcoma.

Analytical Validation of a Highly Quantitative, Sensitive, Accurate, and Reproducible Assay (HERmark) for the Measurement of HER2 Total Protein and HER2 Homodimers in FFPE Breast Cancer Tumor Specimens

We report here the results of the analytical validation of assays that measure HER2 total protein (H2T) and HER2 homodimer (H2D) expression in Formalin Fixed Paraffin Embedded (FFPE) breast cancer tumors as well as cell line controls. The assays are based on the VeraTag technology platform and are commercially available through a central CAP-accredited clinical reference laboratory. The accuracy of H2T measurements spans a broad dynamic range (2-3 logs) as evaluated by comparison with cross-validating technologies. The measurement of H2T expression demonstrates a sensitivity that is approximately 7–10 times greater than conventional immunohistochemistry (IHC) (HercepTest). The HERmark assay is a quantitative assay that sensitively and reproducibly measures continuous H2T and H2D protein expression levels and therefore may have the potential to stratify patients more accurately with respect to response to HER2-targeted therapies than current methods which rely on semiquantitative protein measurements (IHC) or on indirect assessments of gene amplification (FISH).

The HER-2 receptor and breast cancer: ten years of targeted anti-HER-2 therapy and personalized medicine

The human epidermal growth factor receptor (HER-2) oncogene encodes a transmembrane tyrosine kinase receptor that has evolved as a major classifier of invasive breast cancer and target of therapy for the disease. The validation of the general prognostic significance of HER-2 gene amplification and protein overexpression in the absence of anti-HER-2 targeted therapy is discussed in a study of 107 published studies involving 39,730 patients, which produced an overall HER-2-positive rate of 22.2% and a mean relative risk for overall survival (OS) of 2.74. The issue of HER-2 status in primary versus metastatic breast cancer is considered along with a section on the features of metastatic HER-2-positive disease. The major marketed slide-based HER-2 testing approaches, immunohistochemistry, fluorescence in situ hybridization, and chromogenic in situ hybridization, are presented and contrasted in detail against the background of the published American Society of Clinical Oncology-College of American Pathologists guidelines for HER-2 testing. Testing issues, such as the impact of chromosome 17 polysomy and local versus central HER-2 testing, are also discussed. Emerging novel HER-2 testing techniques, including mRNA-based testing by real-time polymerase chain reaction and DNA microarray methods, HER-2 receptor dimerization, phosphorylated HER-2 receptors, and HER-2 status in circulating tumor cells, are also considered. A series of biomarkers potentially associated with resistance to trastuzumab is discussed with emphasis on the phosphatase and tensin homologue deleted on chromosome ten/Akt and insulin-like growth factor receptor pathways. The efficacy results for the more recently approved small molecule HER-1/HER-2 kinase inhibitor lapatinib are also presented along with a more limited review of markers of resistance for this agent. Additional topics in this section include combinations of both anti-HER-2 targeted therapies together as well as with novel agents including bevacizumab, everolimus, and tenespimycin. A series of novel HER-2-targeting agents is also presented, including pertuzumab, ertumaxomab, HER-2 vaccines, and recently discovered tyrosine kinase inhibitors. Biomarkers predictive of HER-2 targeted therapy toxicity are included, and the review concludes with a consideration of HER-2 status in the prediction of response to non-HER-2 targeted treatments including hormonal therapy, anthracyclines, and taxanes.