HER-2 (c-erbB-2) test update: present status and problems

Circulating HER-2 mRNA in the peripheral blood as a potential diagnostic and prognostic biomarker in females with breast cancer

Breast cancer is a prevalent malignant cancer worldwide, and a lack of defined biomarkers for early prognostication contributes to its high associated mortality rate, especially in human epidermal growth factor receptor 2 (HER-2)-positive breast cancer. In the present study, HER-2 mRNA levels in patients were detected prior to surgery and during neoadjuvant chemotherapy to explore its potential diagnostic and prognostic value. Blood samples were collected from 70 patients with breast cancer, including 50 HER-2-negative and 20 HER-2-positive patients, prior to and following surgery (postoperative, n=13; neoadjuvant chemotherapy, n=5); the control group included 35 samples from healthy individuals. The relative mRNA level of HER-2 in blood was determined by one-step reverse transcription-quantitative polymerase chain reaction. HER-2 expression curves of measurements taken during neoadjuvant chemotherapy were compared with the tumor size. A significant difference in the blood HER-2 mRNA level was observed between healthy women and patients with breast cancer (P<0.0001). A cutoff value of 1.512 was established for the circulating HER-2 level in healthy subjects based on the upper 95% confidence interval value of samples from the control group. The level of HER-2 mRNA in blood was associated with the HER-2 status, Ki-67 expression, and lymphovascular invasion in primary tumor tissue samples; however, there was no association with the lymph node status, tumor stage, tumor grade, tumor size, patient age, estrogen or progesterone receptor status of the primary tumor. HER-2 mRNA levels were associated with the response rate, as determined by primary tumor size, in patients who received neoadjuvant chemotherapy. In conclusion, baseline and early changes in peripheral blood HER-2 mRNA indicated that HER-2 mRNA may be a potential diagnostic biomarker for breast cancer and a prognostic marker for predicting the efficacy of neoadjuvant therapy.

Recycling and long-term storage of fluorescence in situ hybridization slides

OBJECTIVES

Although fluorescence in situ hybridization (FISH) technology is adequate, demand exists for additional recycling and long-term storage of FISH slides.

METHODS

Formalin-fixed paraffin-embedded slides derived from breast cancer cases were used for this study. Each slide was probed, and then procedures for removing probes were performed, such as removing the fluorescent probe and diamidino-2-phenylindole signals. Formamide was used for removing probes, and then slides were stored dry at room temperature (22°C), 4°C, -20°C, or -80°C for 101 days. Following storage, each slide was probed in a similar manner to the initial probing. Evaluation was performed using automatic signal count software. Tiles and spots were counted immediately after the initial probing. Reprobed spots for each slide were then compared with the initial probing.

RESULTS

Slides stored at -20°C and -80°C for 101 days showed the best recovery of probing.

CONCLUSIONS

Our approach for probe removal and recycling allows repeated examination of even a limited number of slides.

SHOULD FISH TEST BE PERFORMED TO ALL PATIENTS WITH BREAST CANCER?

CerbB2 receptor determination is very important for the prognosis and treatment of breast cancer. The most used two methods for CerbB2 receptor determination are immunohistochemistry and FISH methods. FISH method is recommended for immunohistochemically CerbB2 (++) patient group. Therefore, even though the immunohistochemically CerbB2 (++) patients are in the same group, FISH test divides the results into two separate groups. Our study compared these two groups in terms of relaps duration. Total of 85 patients from The Kayseri Research and Training Hospital in Kayseri, Kayseri Erciyes University Hospital and Mersin State Hospital were included in this study. The relaps duration of the patients were determined and then compared statistically. When the mean disease free survival was compared for FISH(+) and FISH(-) groups, the mean DFS was 46±5 and 73±8 months. However, the median DFS was 38±9 months for the FISH positive group. No median PFS was reached for FISH (-) group. Immunohistochemically CerbB2 (++) breast cancer patients are considered as in the same group, however actually they have different prognostic features. Similarly, when the immunohistochemical tests and FISH tests are compared for CerbB2 positivity, different results are obtained. As a consequence of that, the therapy alternatives will be changed. Therefore, we conclude that the FISH test should be performed to all patients.

Accurate breast cancer diagnosis through real-time PCR her-2 gene quantification using immunohistochemically-identified biopsies

her-2 gene amplification and its overexpression in breast cancer cells is directly associated with aggressive clinical behavior. The her-2 gene and its Her-2 protein have been utilized for disease diagnosis and as a predictive marker for treatment response to the antibody herceptin. Fluorescent in situ hybridization (FISH) and immunohistochemistry (IHC) are the most common FDA-approved methodologies involving gene and protein quantification, respectively. False positive or negative her-2/Her-2 patient results may result in inappropriate treatment administration. To support accurate quantification and interpretation of results, in this study we have standardized qPCR analysis using previously identified IHC samples, obtaining very significant and clinically useful results.

Analysis of HER2 gene amplification and protein expression in esophageal squamous cell carcinoma

The HER2 gene, which is located on chromosomes 17, is a therapeutic target for cancer. Amplification of HER2 has been described in several tumor types. However, few studies of HER2 gene amplification and protein expression in esophageal carcinoma have been conducted. This study was to investigate the relationship between the expression of HER2/neu and the clinical characteristics, including survival rate, of esophageal squamous carcinoma. The clinical data of 145 patients admitted in Renmin Hospital of Wuhan University, from 2000 to 2005, were reviewed. The HER2 protein expression and gene status in 145 esophageal carcinomas were evaluated using immunohistochemistry and fluorescence in situ hybridization. The survival rate was calculated by the Kaplan-Meier method and the log-rank test using SPSS13.0 software. Compared to normal esophageal epithelium (23/95, 24.2%), HER2 protein was overexpressed in most esophageal squamous carcinoma tissues (60/145, 41.4%), of which 45 (31.0%) were 2+ and 15 (10.4%) were 3+, HER2 overexpression associated significantly with HER2 gene amplification. There is a correlation between the overexpression of HER2 and the differentiation of the carcinoma, the HER2 gene amplification and the differentiation of the carcinoma and the tumor stage. According to univariate analysis, there was a significant difference in survival rates when cases with and without HER-2/neu overexpression or amplification were compared. HER-2/neu amplification/overexpression may be used as an independent prognostic factor in patients with esophageal squamous cancer, and patients with HER-2/neu amplification/overexpression might be potential candidates for new adjuvant therapies that involve the use of humanized monoclonal antibodies.

Her-2/neu evaluation in Sister Mary Joseph's nodule from breast carcinoma: a case report and review of the literature

Sister Mary Joseph's nodule (SMJN) involving the umbilicus can often be a clinical sign of metastatic cancer, but rarely cancer originating from the breast. We report a rare case of umbilical metastases from breast cancer and reviewed the literature. A 54-year-old woman was referred to a pre-surgery clinic for an examination of an umbilical nodule. The patient had a history of ductal breast carcinoma. Cytological smear from fine needle aspiration showed epithelial neoplastic cells resembling those of breast carcinoma. Neoplastic cells from tissue were positive for cytokeratin 8-18, estrogen and progesterone receptor and negative for E-cadherin and had a low proliferative index. Her-2/neu immunodetection showed a 2+ equivocal positive rate, but Her-2/neu gene amplification was found on the cytological smear by fluorescence in situ hybridization analysis. Similar results were obtained within a tissue section. Concordant findings have been obtained when comparing the recent American Society of Clinical Oncology/College of American Pathologists scoring system. Fine needle aspiration from the SMJN is a useful tool for the diagnosis of metastatic breast cancer. Furthermore, the predictive biomarkers for tumors of the breast, hormonal receptors and Her-2/neu not only assist with the identification of the source of the metastatic disease but also provide clinical information for patient management.

Changes in HER2 expression in breast cancer xenografts after therapy can be quantified using PET and (18)F-labeled affibody molecules

In vivo imaging of human epidermal growth factor receptor type 2 (HER2) expression may allow direct assessment of HER2 status in tumor tissue and provide a means to quantify changes in receptor expression after HER2-targeted therapies. This work describes the in vivo characterization of the HER2-specific N-2-(4-(18)F-fluorobenzamido)ethyl]maleimide ((18)F-FBEM)-Z(HER2:342) Affibody molecule and its application to study the effect of 17 (dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG) on HER2 expression by PET.

METHODS

To assess the correlation of signal observed by PET with receptor expression, we administered the tracer to athymic nude mice bearing subcutaneous human breast cancer xenografts with different levels of HER2 expression. To study the downregulation of HER2, we treated the mice with 4 doses (40 mg/kg) of 17-DMAG, an inhibitor of heat-shock protein 90, known to decrease HER2 expression. The animals were scanned before and after treatment. After the last scan, the mice were euthanized and tumors were frozen for receptor analysis.

RESULTS

The tracer was eliminated quickly from the blood and normal tissues, providing high tumor-to-blood and tumor-to-muscle ratios as early as 20 min after injection. The high-contrast images between normal and tumor tissue were recorded for BT474 and MCF7/clone18 tumors. Low but still detectable uptake was observed for MCF7 tumors, and none for MDA-MB-468. The signal correlated with the receptor expression as assessed by immunohistochemistry, Western blot, and enzyme-linked immunosorbent assay. The levels of HER2 expression estimated by post-treatment PET decreased 71% (P < 4 x 10(-6)) and 33% (P < 0.002), respectively, for mice bearing BT474 and MCF7/clone18 tumors. These changes were confirmed by the biodistribution studies, enzyme-linked immunosorbent assay, and Western blot.

CONCLUSION

Our results suggest that the described (18)F-FBEM-Z(HER2:342) Affibody molecule can be used to assess HER2 expression in vivo by PET and monitor possible changes of receptor expression in response to therapeutic interventions.

Gene and chromosomal alterations in sporadic breast cancer: correlation with histopathological features and implications for genesis and progression

A number of gene and chromosome alterations have been identified in sporadic breast carcinomas, and their clinical implications have been investigated. Changes in proto-oncogenes and tumor-suppressor genes, e.g., HER2, p53, and E-cadherin, and various numerical and structural chromosome alterations are strongly correlated with histological type and grade in breast carcinomas. The amount of information on these alterations has been dramatically increased by the introduction of high-throughput molecular cytogenetic approaches. In the near future, breast cancers will be classified into specific groups according to their profile of gene and chromosome alterations, allowing more effective personalized therapies targeting the associated molecular pathways.

Oncoprotein HCCR-1 expression in breast cancer is well correlated with known breast cancer prognostic factors including the HER2 overexpression, p53 mutation, and ER/PR status

Background

Oncoprotein HCCR-1 functions as a negative regulator of the p53 and contributes breast tumorigenesis. The serum HCCR-1 assay is useful in diagnosing breast cancer and mice transgenic for HCCR developed breast cancers. But it is unknown how HCCR-1 contributes to human breast tumorigenesis.

Methods

Oncogene HCCR-1 expression levels were determined in normal breast tissues, breast cancer tissues and cancer cell lines. We examined whether HCCR-1 protein expression in breast cancer is related to different biological characteristics, including ER, PR, p53 genotype, and HER2 status in 104 primary breast cancer tissues using immunohistochemical analyses.

Results

HCCR-1 was upregulated in breast cancer cells and tissues compared with normal breast tissues. In this study, overexpression of HCCR-1 was well correlated with known breast cancer prognostic markers including the presence of steroid receptors (ER and PR), p53 mutation and high HER2 overexpression. HCCR-1 was not detected in the ER-negative, PR-negative, p53 negative and low HER2 breast cancer tissues. These data indicate that the level of HCCR-1 in breast cancer tissues is relatively well correlated with known breast cancer factors, including the HER2 overexpression, p53 mutation, and ER/PR status.

Conclusion

Determination of HCCR-1 levels as options for HER2 testing is promising although it needs further evaluation.

Individualization of breast cancer based on histopathological features and molecular alterations

Histopathological findings and molecular alterations well reflect the biological properties of individual primary breast carcinomas. Specifically, pT (size of the invasive component), pN (number of metastatic lymph nodes), histological or nuclear grade, lymphovascular invasion, hormone receptors, and HER2 (c-erbB-2) gene overexpresson or amplification are known to be effective markers for assessing the risk of operable primary breast carcinoma, albeit incompletely. It is expected that additional molecular markers and novel diagnostic tools will be developed in the future to facilitate a more accurate characterization of higher risk node-negative breast carcinomas.

[Availability of fine needle aspirates for the assessment of HER2 gene amplification in invasive breast cancer patients]

BACKGROUND

FISH and immunohistochemistry (IHC) on formalin-fixed paraffin embedded (FFPE) tissue are currently used in the clinical laboratory to determine HER2 status in invasive breast cancer patients. Since tissue-based methods are relatively time-consuming and have a limitation for standardization of procedure, we evaluated the availability of fine needle aspirates (FNA) for the assessment of HER2 status in invasive breast cancer patients.

METHODS

FNA were obtained from 51 invasive breast cancer patients and were submitted for the evaluation of HER2 status. After invasive breast cancer components were ascertained by morphological evaluation, HER2 gene amplification was evaluated by FISH. The results of HER2 FISH on FNA cells were compared with those of both FISH and IHC on corresponding FFPE tissues. FISH results were interpreted by American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines issued in 2007.

RESULTS

Of 51 FNA specimens, one was excluded due to an insufficient number of cancer cells for tests. Excluding the cases that showed 'equivocal' results, 47 (98%) out of 48 cases were concordant between the results of FISH on FNA and FISH on corresponding FFPE tissue (kappa, 0.969), and 43 (93%) out of 46 cases were concordant between the results of FISH on FNA and IHC on corresponding FFPE tissue (kappa, 0.912).

CONCLUSIONS

An excellent correlation was found between FISH on FNA cells and corresponding FFPE sections. We recommend FNA specimens for more rapid determination of HER2 status by FISH, which will be helpful for patient selection for individualized therapy.

Evaluation of gene amplification and protein expression of HER-2/neu in esophageal squamous cell carcinoma using Fluorescence in situ Hybridization (FISH) and immunohistochemistry

Background

Esophageal squamous cell carcinoma (ESCC) is the sixth most frequent neoplasia in Brazil. It is usually associated with a poor prognosis because it is often at an advanced stage when diagnosed and there is a high frequency of lymph node metastases. It is important to know what prognostic factors can facilitate diagnosis, optimize therapeutic decisions, and improve the survival of these patients. A member of the epidermal growth factor receptor (EGFR) family, c-erbB-2, has received much attention because of its therapeutic implications; however, few studies involving fluorescence in situ hybridization (FISH) analysis of HER-2/neu gene amplification and protein expression in ESCC have been conducted. The aim of this study was to verify the presence of HER-2/neu gene amplification using FISH, and to correlate the results with immunohistochemical expression and clinical-pathological findings.

Methods

One hundred and ninety-nine ESCC cases were evaluated using the Tissue Microarray (TMA) technique. A polyclonal antibody against c-erbB-2 was used for immunohistochemistry. Analyses were based on the membrane staining pattern. The results were classified according to the Herceptest criteria (DAKO): negative (0/1+), potential positive (2+) and positive (3+). The FISH reactions were performed according to the FISH HER2 PharmDx (DAKO) protocol. In each case, 100 tumor nuclei were evaluated. Cases showing a gene/CEN17 fluorescence ratio ≥ 2 were considered positive for gene amplification.

Results

The c-erbB-2 expression was negative in 117/185 cases (63.2%) and positive in 68 (36.8%), of which 56 (30.3%) were 2+ and 12 (6.5%) were 3+. No significant associations were found among protein expression, clinicopathological data and overall survival. Among the 47 cases analyzed, 38 (80.9%) showed no gene amplification while 9 (19.1%) showed amplification, as demonstrated by FISH. Cases that were negative (0/1+) and potential positive (2+) for c-erbB-2 expression by immunohistochemistry showed no gene amplification. However, all cases with gene amplification were positive (3+) by immunohistochemistry. According to univariate analysis, there was a significant difference (p = 0.003) in survival rates when cases with and without HER-2/neu amplification were compared.

Conclusion

Our data demonstrate the correspondence between gene amplification and protein expression of HER-2/neu. Gene amplification is an indicator of poor prognosis in ESCC.

Endosialin protein expression and therapeutic target potential in human solid tumors: sarcoma versus carcinoma

PURPOSE

Endosialin/CD248/tumor endothelial marker 1 is expressed in stromal cells, endothelial cells, and pericytes in various tumors; however, few studies have focused on expression in malignant cells.

EXPERIMENTAL DESIGN

We studied expression of endosialin in clinical specimens, cell culture, and animal models and designed an anti-endosialin therapeutic prototype.

RESULTS

Fifty human tumor cell lines and 6 normal cell types in culture were assayed by reverse transcription-PCR and/or flow cytometry for endosialin. Cell surface protein was found on 7 sarcoma lines, 1 neuroblastoma, and 4 normal cell types in culture. A fully human anti-endosialin antibody bound to human A-673 Ewing's sarcoma cells and SK-N-AS neuroblastoma cells but not HT-1080 cells. Exposure of cells to an anti-human IgG conjugated to saporin resulted in growth inhibition only of endosialin-expressing cells. Endosialin expression was assessed by immunohistochemistry in 250 clinical specimens of human cancer including 20 cancer subtypes. Endosialin is frequently found in human cancers. Endosialin expression is mainly a perivascular feature in carcinomas, with some expression in stromal cells. In sarcomas, endosialin is expressed by malignant cells, perivascular cells, and stromal cells. Development and characterization of experimental models for studying endosialin biology in sarcomas and evaluating anti-endosialin therapies is presented.

CONCLUSIONS

Findings suggest that an anti-endosialin immunotoxin might be a promising therapeutic approach for endosialin-positive neoplasia, especially synovial sarcoma, fibrosarcoma, malignant fibrous histiocytoma, liposarcoma, and osteosarcoma. Thus, a diagnostic/therapeutic targeted therapeutic approach to treatment of endosialin-expressing tumors may be possible.

Genetic clustering of clear cell renal cell carcinoma based on array-comparative genomic hybridization: its association with DNA methylation alteration and patient outcome

PURPOSE

The aim of this study was to clarify genetic and epigenetic alterations occurring during renal carcinogenesis.

EXPERIMENTAL DESIGN

Copy number alterations were examined by array-based comparative genomic hybridization analysis using an array harboring 4,361 bacterial artificial chromosome clones, and DNA methylation alterations on CpG islands of the p16, human MutL homologue 1, von Hippel-Lindau, and thrombospondin 1 genes and the methylated in tumor (MINT-1, MINT-2, MINT-12, MINT-25, and MINT-31) clones were examined in 51 clear cell renal cell carcinomas (RCC).

RESULTS

By unsupervised hierarchical clustering analysis based on copy number alterations, clear cell RCCs were clustered into the two subclasses, clusters A (n=34) and B (n=17). Copy number alterations were accumulated in cluster B. Loss of chromosome 3p and gain of 5q and 7 were frequent in both clusters A and B, whereas loss of 1p, 4, 9, 13q, and 14q was frequent only in cluster B. The average number of methylated CpG islands in cluster B was significantly higher than those in cluster A. Clear cell RCCs showing higher histologic grades, vascular involvement, renal vein tumor thrombi, and higher pathologic stages were accumulated in cluster B. The recurrence-free and overall survival rates of patients in cluster B were significantly lower than those of patients in cluster A. Multivariate analysis revealed that genetic clustering was a predictor of recurrence-free survival and was independent of histologic grade and pathologic stage.

CONCLUSIONS

This genetic clustering of clear cell RCC is significantly associated with regional DNA hypermethylation and may become a prognostic indicator for patients with RCC.

Coordinated epidermal growth factor receptor pathway gene overexpression predicts epidermal growth factor receptor inhibitor sensitivity in pancreatic cancer

The epidermal growth factor receptor (EGFR) inhibitor erlotinib is approved for treatment of pancreatic cancer but the overall activity is minimal, and known predictive factors for EGFR inhibitor efficacy are infrequent in this disease. We tested the hypothesis that global activation of the EGFR pathway is predictive of EGFR inhibitor efficacy. Pancreatic cancer tumors directly xenografted at surgery were treated with the EGFR inhibitors erlotinib and cetuximab and analyzed for biological features. Two of 10 tumors were sensitive, and by global gene expression profiling with gene set enrichment analysis, the EGFR pathway was highly expressed in sensitive compared with resistant tumors. The core gene components driving EGFR pathway overexpression were pathway ligands and positive effectors. In a prospective validation, the EGFR pathway-based signature correctly predicted anti-EGFR treatment response in eight additional tumors and was not predictive of response to gemcitabine and CI1040 (a MEK inhibitor). Analysis of EGFR, KRAS, and PIK3CA mutations and gene amplification by fluorescence in situ hybridization and multiplex ligation-dependent probe amplification showed that none of these genetic abnormalities were neither predictive nor responsible for the EGFR pathway activation. Coordinated overexpression of the EGFR pathway predicts susceptibility to EGFR inhibitors in pancreatic cancer. These results suggest a phenomenon of pathway addiction and support the value of unbiased system biology approaches in drug development.

Trastuzumab therapy vs tetracycline controlled ERBB2 downregulation: influence on tumour development in an ERBB2-dependent mouse tumour model

Trastuzumab (Herceptin) has improved therapy of breast cancer. Only patients overexpressing ERBB2 are treated with trastuzumab, whereas its use in tumours without ERBB2 expression is useless. This led to the concept that the subgroup of trastuzumab-sensitive tumours is ‘ERBB2-dependent’, meaning that ERBB2 signalling is indispensable for growth of these tumours. We used a mouse model that allows anhydrotetracycline (ATc)-controlled downregulation of ERBB2 in tumour tissue. ERBB2 mRNA and protein expression were downregulated below detection limit leading to a macroscopically complete tumour remission within 14 days. Tumour remission was accompanied by a strong decrease in proliferation, a moderate increase in apoptosis, as well as dephosphorylation of ERK1/2 and AKT/PKB. These data clearly indicate ERBB2 dependence. Therefore, a high sensitivity to trastuzumab may be suspected. Surprisingly, trastuzumab caused a much weaker effect compared to ATc-induced ERBB2 downregulation, although a decrease in ERBB2 membrane localisation was induced. Only a slight decrease in proliferation and a weak transient increase in apoptosis were observed. Interestingly, tumours responded to trastuzumab by a sharp fivefold increase in phosphorylated AKT/PKB as well as a 3.5- and 5.3-fold increase in AKT1 and AKT2 mRNA levels, respectively. In conclusion, ‘ERBB2 dependence’ is not sufficient to define trastuzumab-responsive tumours. The suboptimal effect of trastuzumab compared to the maximally possible effect induced by ATc demonstrates a high potential for improved ERBB2 blocking therapies.

Predicting the efficacy of trastuzumab-based therapy in breast cancer: current standards and future strategies

Breast cancer is the most common female malignancy in many industrialized countries. Approximately one fourth of all women diagnosed with early breast cancer present with tumors that are characterized by erbB2 amplification. While the associated Her-2/neu receptor overexpression results in a high risk of relapse and poor prognosis, these tumors also represent a target for a selective monoclonal antibody therapy with trastuzumab (Herceptin). The combination of trastuzumab with chemotherapy has led to a considerable reduction of recurrences and to a significant reduction in breast cancer mortality both in the adjuvant and metastatic setting. Unfortunately, despite Her-2/neu overexpression, not all patients equally benefit from trastuzumab treatment, and almost all women with metastatic breast cancer eventually progress during antibody therapy. Moreover, trastuzumab is burdened with cardiotoxicity, thus increasing the risk of symptomatic congestive heart failure. In addition, the marginal costs for a 1 year therapy of trastuzumab-based therapy, which is currently considered to be the most effective treatment regimen in the adjuvant setting, may amount for up to US$ 40.000. Testing for erbB2 oncogene amplification by fluorescence in situ hybridization (FISH) and chromogenic in situ hybridization (CISH), respectively, and staining for Her-2/neu receptor overexpression by immunohistochemistry (IHC) represent the current standard for determining patient eligibility for trastuzumab-based therapy. However, while the negative predictive value of these assays for predicting the absence of benefit from trastuzumab-based therapy is sufficiently high, their positive predictive value remains insufficient, i.e. only a proportion of patients selected by these tests substantially benefit from trastuzumab-containing regimen. Accordingly, over the last years a number of biomarkers have been evaluated in their potential to predict response to trastuzumab-based therapies. These include markers auf activation of Her-2/neu (e.g., tyrosine phosphorylated Her-2/neu in tissue and cleaved Her-2/neu extracellular domain in serum) and its dimerization partners (e.g., EGFR), respectively, but also components of Her-2/neu-induced downstream signaling pathways that are crucial for the growth inhibitory effects of trastuzumab (e.g., PTEN and PI3K). Other parameters, such as topoisomerase-II alpha and c-myc co-amplifications, have also been identified as potentially useful predictors of response to trastuzumab-based chemotherapy regimen. While the benefit of these predictive biomarkers in the metastatic setting is currently explored, their usefulness in the adjuvant setting is still largely unknown. It is, however, undisputable that, within the group of Her-2/neu overexpressing tumors, further response predictors are needed in order to minimize trastuzumab-associated side effects, and to reduce the considerable societal costs that are associated with trastuzumab-based treatment regimen.

Diagnostic significance of allelic imbalance in cancer

Allelic imbalance (AI), a deviation from the normal 1:1 ratio of maternal and paternal alleles, occurs in virtually all solid and blood-borne malignancies. The frequency and spectrum of AI in a tumor cell reflects the karyotypic complexity of the cancer genome. Hence, many investigations have assessed the extent of AI to analyze differences between normal and tumor tissues in a variety of different organs. In this review, the authors describe established and emerging technologies used to assess the extent of AI in human tissues, and their application in the diagnosis of cancer. The four major methods to be reviewed represent powerful and widely used tools for the identification of allelic imbalances accompanying cancer initiation and progression. These are fluorescent in situ hybridization, comparative genomic hybridization, single nucleotide polymorphism arrays and the use of microsatellite markers. For each method, the authors provide a brief description of the approach and elaborate on specific studies that highlight its utility in the diagnosis of human cancers.

Metallographic in situ hybridization

Metallographic methods, in which a target is visualized using a probe or antibody that deposits metal selectively at its binding site, offers many advantages for bright-field in situ hybridization (ISH) detection as well as for other labeling and detection methods. Autometallographically enhanced gold labeling procedures have demonstrated higher sensitivity than conventional enzyme chromogens. Enzyme metallography, a novel procedure in which an enzymatic probe is used to deposit metal directly from solution, has been used to develop bright-field ISH methods for HER2 gene determination in breast cancer and other biopsy specimens. It provides the highest level of sensitivity and resolution, both for visualizing endogenous gene copies in nonamplified tissues and for resolving multiple gene copies to allow copy enumeration in amplified tissues without the need for oil immersion or fluorescence optics. An automated enzyme metallography procedure, silver ISH, has been developed for use in slide-staining instruments. Metallographic staining also provides excellent results for immunohistochemistry and may be combined with other staining procedures for the simultaneous detection of more than one gene or combinations of genes and proteins.

MN1 overexpression induces acute myeloid leukemia in mice and predicts ATRA resistance in patients with AML

Overexpression of wild-type MN1 is a negative prognostic factor in patients with acute myeloid leukemia (AML) with normal cytogenetics. We evaluated whether MN1 plays a functional role in leukemogenesis. We demonstrate using retroviral gene transfer and bone marrow (BM) transplantation that MN1 overexpression rapidly induces lethal AML in mice. Insertional mutagenesis and chromosomal instability were ruled out as secondary aberrations. MN1 increased resistance to all-trans retinoic acid (ATRA)–induced cell-cycle arrest and differentiation by more than 3000-fold in vitro. The differentiation block could be released by fusion of a transcriptional activator (VP16) to MN1 without affecting the ability to immortalize BM cells, suggesting that MN1 blocks differentiation by transcriptional repression. We then evaluated whether MN1 expression levels in patients with AML (excluding M3-AML) correlated with resistance to ATRA treatment in elderly patients uniformly treated within treatment protocol AMLHD98-B. Strikingly, patients with low MN1 expression who received ATRA had a significantly prolonged event-free (P = .008) and overall (P = .04) survival compared with patients with either low MN1 expression and no ATRA, or high MN1 expression with or without ATRA. MN1 is a unique oncogene in hematopoiesis that both promotes proliferation/self-renewal and blocks differentiation, and may become useful as a predictive marker in AML treatment.

The use of an in vitro adenosine triphosphate-based chemotherapy response assay to predict chemotherapeutic response in breast cancer

The adenosine triphosphate-based chemotherapy response assay (ATP-CRA) has the advantages of standardization, evaluability, reproducibility, and accuracy, and can be performed on relatively small numbers of tumor cells. A total of 43 patients were enrolled in the present study, and chemosensitivity tests were successfully performed in 40 (93.0%) of these patients. Twenty of the 40 received neoadjuvant chemotherapy or chemotherapy for metastatic breast cancer. The chemotherapy regimens used were doxorubicin plus docetaxel (n=9, 45.0%) or doxorubicin plus paclitaxel (n=11, 55.0%). Mean cell death rate, as determined by ATP-CRA, was lower in non-responders than in responders to therapy (P=0.012). Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for ATP-CRA were 78.6%, 100%, 100%, 66.7%, and 85.0%, respectively. Diagnostic accuracy achieved by immunohistochemistry using estrogen receptor or progesterone receptor was lower than that achieved using ATP-CRA. Expression of p53, erb-B2, Ki67, Bcl-2, Bcl-xL, and annexin I was not significantly associated with response to chemotherapy. Our results show that ATP-CRA has high specificity and positive predictive value for predicting response to chemotherapy.

Expression of ontogene C-erbB-2 and its correlations with invasion and metastasis in colorectal carcinoma

AIM: To investigate the expression of oncogene C-erbB-2 and its significance in colorectal carcinoma.

METHODS: Immunohistochemical technique (SP) was performed to detect the expression of oncogene C-erbB-2 in 69 cases of colorectal carcinoma and its corresponding tissues from patients received curative resection.

RESULTS: The expression of C-erbB-2 was mainly found in cell membrane and cytoplasm of colorectal carcinoma tissues with a positive rate of 65.2% (45/69), which was significantly higher than that in the tissues of benign tumor (2/20, P < 0.05). The positive rate of C-erbB-2 expression had significant difference between colorectal cancer (65.2%) and its surrounding tissues (mesenteric: 47.8%, normal cancer-adjacent: 30.4%, distant resection margin: 13.0%; all P < 0.05). The expression of C-erbB-2 was significantly correlated with the gross morphology, differentiation of the tumor cells, clinical staging (Dukes staging) and lymph node metastasis (P < 0.05), but not with the age, sex of patients, tumor location and size, as well as distant metastasis (P > 0.05). The expression of oncogene C-erbB-2 in the mesenteric margin and cancer-adjacent tissues was markedly different between routine histology and immunohistochemistry (P < 0.05).

CONCLUSION: The expression of C-erbB-2 gene is positively correlated with tumor invasion and metastasis in colorectal carcinoma, and it is a marker in evaluating the prognosis of colorectal carcinoma.