HER2 Gene Amplification Testing by Fluorescent In Situ Hybridization (FISH): Comparison of the ASCO-College of American Pathologists Guidelines With FISH Scores Used for Enrollment in Breast Cancer International Research Group Clinical Trials

Purpose

ASCO and the College of American Pathologists (ASCO-CAP) recently recommended further changes to the evaluation of human epidermal growth factor receptor 2 gene (HER2) amplification by fluorescent in situ hybridization (FISH). We retrospectively assessed the impact of these new guidelines by using annotated Breast Cancer International Research Group (BCIRG) -005, BCIRG-006, and BCIRG-007 clinical trials data for which we have detailed outcomes.

Patients and Methods

The HER2 FISH status of BCIRG-005/006/007 patients with breast cancers was re-evaluated according to current ASCO-CAP guidelines, which designates five different groups according to HER2 FISH ratio and average HER2 gene copy number per tumor cell: group 1 (in situ hybridization [ISH]–positive): HER2-to-chromosome 17 centromere ratio ≥ 2.0, average HER2 copies ≥ 4.0; group 2 (ISH-positive): ratio ≥ 2.0, copies < 4.0; group 3 (ISH-positive): ratio < 2.0, copies ≥ 6.0; group 4 (ISH-equivocal): ratio < 2.0, copies ≥ 4.0 and < 6.0; and group 5 (ISH-negative): ratio < 2.0, copies < 4.0. We assessed correlations with HER2 protein, clinical outcomes by disease-free survival (DFS) and overall survival (OS) and benefit from trastuzumab therapy (hazard ratio [HR]).

Results

Among 10,468 patients with breast cancers who were successfully screened for trial entry, 40.8% were in ASCO-CAP ISH group 1, 0.7% in group 2; 0.5% in group 3, 4.1% in group 4, and 53.9% in group 5. Distributions were similar in screened compared with accrued subpopulations. Among accrued patients, FISH group 1 breast cancers were strongly correlated with immunohistochemistry 3+ status (P < .0001), whereas groups 2, 3, 4, and 5 were not; however, groups 2, 4 and, 5 were strongly correlated with immunohistochemistry 0/1+ status (all P < .0001), whereas group 3 was not. Among patients accrued to BCIRG-005, group 4 was not associated with significantly worse DFS or OS compared with group 5. Among patients accrued to BCIRG-006, only group 1 showed a significant benefit from trastuzumab therapy (DFS HR, 0.71; 95% CI, 0.60 to 0.83; P < .0001; OS HR, 0.69; 95% CI, 0.55 to 0.85; P = .0006), whereas group 2 did not.

Conclusion

Our findings support the original categorizations of HER2 by FISH status in BCIRG/Translational Research in Oncology trials.

Tissue Microarrays

Modern next-generation sequencing and microarray technologies allow for the simultaneous analysis of all human genes on the DNA, RNA, miRNA, and methylation RNA level. Studies using such techniques have lead to the identification of hundreds of genes with a potential role in cancer or other diseases. The validation of all of these candidate genes requires in situ analysis of high numbers of clinical tissues samples. The tissue microarray technology greatly facilitates such analysis. In this method minute tissue samples (typically 0.6 mm in diameter) from up to 1000 different tissues can be analyzed on one microscope glass slide. All in situ methods suitable for histological studies can be applied to TMAs without major changes of protocols, including immunohistochemistry, fluorescence in situ hybridization, or RNA in situ hybridization. Because all tissues are analyzed simultaneously with the same batch of reagents, TMA studies provide an unprecedented degree of standardization, speed, and cost efficiency.

Loss of RNA-binding motif protein 3 expression is associated with right-sided localization and poor prognosis in colorectal cancer

AIMS

RNA-binding motif protein 3 (RBM3) has recently been suggested as a prognostic biomarker in an array of human cancers. This study aimed to examine its effects in colorectal cancers.

METHODS AND RESULTS

RBM3 expression was analysed by immunohistochemistry on a tissue microarray containing 1800 colorectal cancers (CRCs). Nuclear RBM3 immunohistochemical staining was found in 95.9% of all interpretable CRCs. Loss of RBM3 expression was linked to advanced tumour stage (P < 0.0001), right-sided tumour localization (P < 0.0001), and poor prognosis (P = 0.0003). In a multivariable analysis including RBM3 staining, tumour grade, tumour stage, and nodal status, only tumour stage and nodal status proved to be independent prognostic markers (P < 0.0001 each), whereas the prognostic impact of RBM3 staining was not significant (P = 0.2655).

CONCLUSIONS

Our observations indicate that loss of RBM3 expression is an unfavourable prognostic marker in CRC, and is linked to right-sided tumour localization.

Prognostic relevance of Bcl-2 overexpression in surgically treated prostate cancer is not caused by increased copy number or translocation of the gene

BACKGROUND

Overexpression of anti-apoptotic Bcl-2 plays a role in prostate cancer progression, particularly in transformation to androgen-independent disease. Androgen-independent prostate cancers have been shown to harbor Bcl-2 gene copy number gains frequently suggesting that this genetic alteration might play a role in Bcl-2 overexpression. The relation of Bcl-2 overexpression and copy number gains or translocation of the BCL-2 gene in prostate cancer under hormone-naïve conditions is unknown.

METHODS

Prostate cancers of 3,261 hormone-naïve patients undergoing radical prostatectomy were arrayed in a TMA with one tissue core (diameter 0.6 mm) per tumor. Bcl-2 immunohistochemistry, analyzed for Bcl-2 expression level (negative, low, and high), was correlated with clinical, histopathological and molecular (Ki67, p53) tumor features, and biochemical failure. Cancers with high-level Bcl-2 expression were evaluated for genetic aberrations by fluorescence in situ hybridization (FISH).

RESULTS

Bcl-2 expression was significantly up-regulated in tumors with aggressive phenotype as indicated by high Gleason score (P < 0.0001), advanced stage (P < 0.0001), and high proliferation index (P = 0.0114). The different Bcl-2 expression levels translated into significantly different survival curves showing better outcome for patients with lower Bcl-2 levels. The prognostic information obtained from the anti-apoptotic Bcl-2 was independent from the proliferation index (Ki67) of the cancer. FISH analysis detected no copy number gains or translocation of the Bcl-2 gene.

CONCLUSION

Bcl-2 overexpression in prostate cancers under hormone-naïve conditions is not associated with increased copy numbers of the gene. This suggests that these frequently detected genetic alterations in androgen-independent tumors occur late in prostate cancer progression.

The impact of the number of cores on tissue microarray studies investigating prostate cancer biomarkers

Most tissue microarray studies have used a single 0.6-mm tissue core per donor tissue. It has been suggested that multiple cores per donor can increase the representativity of tissue microarray studies. To estimate the potential benefit of multiple cores, we analyzed Ki67 and p53 in triplet cores taken from three different areas of 3,261 prostate cancer tissue blocks. Both p53 and Ki67 labeling index were linked to advanced tumor stage (p<0.0001 each), Gleason score (p<0.0001), and early PSA recurrence (p<0.0001) independently of whether the 3 tissue spots were analyzed separately or combined for a consensus result. The rate of positive findings increased with the amount of analyzed tissue. The average Ki67 labeling index was higher in tumors with 3 interpretable spots (5.3±5.6) as compared to two (4.1±4.7) or one interpretable spot (4.1±4.2, p<0.0001). For p53, tumors with three interpretable spots were positive in 3.8% of cases, and tumors with 1 or 2 interpretable spots in 1.9% only (p=0.003). These data demonstrate that using multiple cores in a tissue microarray does not necessarily increase the ability to identify associations of biomarkers with tumor phenotype and prognosis but has always the disadvantage of additional work and tissue requirements. Multiple cores may even lead to statistical problems if unequal amounts of tissue are analyzed per tumor.

Heterogenous high-level HER-2 amplification in a small subset of colorectal cancers

HER-2 is the molecular target for antibody-based treatment of breast cancer (trastuzumab). The potential benefit of anti-HER-2 therapy is currently investigated in several other HER-2 amplified cancers. For example, trastuzumab was recently shown to be effective in HER-2 positive gastric cancer. To address the potential applicability of anti-HER-2 therapy in colorectal cancer, tissue microarray sections and colorectal resection specimens of 1851 colorectal cancers were analyzed for HER-2 overexpression and amplification using FDA approved reagents for immunohistochemistry and fluorescence in situ hybridization. HER-2 amplification was seen in 2.5% and HER-2 overexpression in 2.7% of 1439 interpretable colorectal cancers. Amplification was often high level with HER-2 copies ranging from 4 to 60 per tumor cell and was strongly related to protein overexpression. HER-2 amplification and overexpression were unrelated to histological tumor type, tumor localization, grading, pT, pN, pM or survival. As heterogeneity of drug target expression could represent a major drawback for targeted cancer therapy we next studied HER-2 heterogeneity in selected cases. Extensive evaluation of all available large sections from patients with HER-2 positive colorectal cancer revealed heterogenous findings in 3 of 4 cases. In summary, high-level HER-2 amplification occurs in a small fraction of colorectal cancers. Heterogeneity of amplification may limit the utility of anti- HER-2 therapy in some of these tumors and therefore, adequate clinical trials are needed to further evaluate this approach.

Low level HER2 overexpression is associated with rapid tumor cell proliferation and poor prognosis in prostate cancer

PURPOSE

The HER2 oncogene is involved in the biology of many different tumor types and serves as a prognostic marker and a therapeutic target in breast cancer. In contrast to breast cancer, studies on Her2 overexpression and gene amplification in prostate cancer have yielded different results. The purpose of this study was to learn more on the prevalence and clinical significance of HER2 amplification and overexpression in prostate cancer.

EXPERIMENTAL DESIGN

A tissue microarray containing >2,000 prostate cancers with follow-up data was used. Tissue microarray sections were analyzed on protein and DNA level using two different antibodies (HercepTest, DAKO; Novocastra NCL-CB11) and fluorescence in situ hybridization.

RESULTS

Immunohistochemical analyses showed highly similar results for both antibodies. Detectable Her2 immunostaining was observed in 17.2% for the HercepTest and in 22.5% for the Novocastra antibody with the vast majority of cases showing 1+ or 2+ staining. For both antibodies (HercepTest/Novocastra), significant associations were found between positive staining and high Gleason grade (P < 0.0001, both), advanced pT stage (P < 0.0001/P = 0.0015), rapid tumor cell proliferation (P = 0.0004/P = 0.0071), and tumor recurrence (P < 0.0001, both). HER2 amplification was only found in 1 of 2,525 analyzable cases (0.04%).

CONCLUSIONS

Low-level Her2 overexpression occurs at relevant frequency in prostate cancer and in the absence of gene amplification. Increased Her2 expression may potentially lead to an aggressive behavior of tumor cells through the stimulation of tumor cell proliferation because Her2 staining was shown to be significantly associated with Ki67 labeling index. These data argue for reconsidering anti-Her2 therapy, possibly with modified approaches.

Tissue microarrays

Modern array technologies allow for the simultaneous screening of virtually all human genes on the DNA and RNA level. Studies using such techniques have lead to the identification of hundreds of genes with a potential role in cancer or other diseases. The validation of all of these candidate genes requires in situ analysis of high numbers of clinical tissues samples. The tissue microarray (TMA) technology greatly facilitates such analysis. In this method, minute tissue samples (0.6 mm in diameter) from up to 1,000 different tissues can be analyzed on one microscope glass slide. All in situ methods suitable for histological studies can be applied to TMAs without major changes of protocols, including immunohistochemistry, fluorescence in situ hybridization, or RNA in situ hybridization. Because all tissues are analyzed simultaneously with the same batch of reagents, TMA studies provide an unprecedented degree of standardization, speed, and cost efficiency.

Immunohistochemical analysis of tissue microarrays

Immunohistochemistry (IHC) is the gold standard methodology for in-situ protein expression analysis in tissue samples. The combination of IHC and tissue microarray (TMA) technology allows for the simultaneous analysis of hundreds of tissue samples with an unprecedented degree of experimental standardization. The same immunostaining protocols used for conventional large sections can be used for TMAs, including antigen retrieval procedures for staining of routinely archived formalin-fixed tissue samples. The development of optimal IHC protocols is highly important for TMA studies because minor protocol variations often have a marked impact on the outcome of the staining. Preabsorption and isotype-specific control experiments should be included as the last step in protocol development to proof target protein-specific binding. Such controls are particularly important for new antibodies with unknown staining patterns.

Recipient block TMA technique

New high-throughput screening technologies have led to the identification of hundreds of genes with a potential role in cancer or other diseases. One way to prioritize the leads obtained in such studies is to analyze a large number of tissues for candidate gene expression. The TMA methodology is now an established and frequently used tool for high-throughput tissue analysis. The recipient block technology is the "classical" method of TMA making. In this method, minute cylindrical tissue punches typically measuring 0.6 mm in diameter are removed from donor tissue blocks and are transferred into empty "recipient" paraffin blocks. Up to 1,000 different tissues can be analyzed in one TMA block. The equipment is affordable and easy to use in places where basic skills in histology are available.

Immunological microenvironment in prostate cancer: high mast cell densities are associated with favorable tumor characteristics and good prognosis

BACKGROUND

Number of intratumoral mast cells predicts survival in various cancers. The prognostic significance of such mast cells in surgically treated prostate cancer is unknown.

METHODS

Mast cell densities were determined in prostate cancer samples of more than 2,300 hormone-naïve patients using a tissue microarray format in correlation with clinical follow-up data. Mast cells were visualized immunohistochemically (c-kit). All patients were homogeneously treated by radical prostatectomy at a single institution.

RESULTS

Mast cells were present in 95.9% of the tumor samples. Median mast cell number on the tissue spot was 9 (range: 0-90; median density: 31 mast cells/mm(2)). High mast cell densities were significantly associated with more favorable tumors having lower preoperative prostate-specific antigen (P = 0.0021), Gleason score (P < 0.0001) and tumor stage (P < 0.0001) than tumors with low mast cell densities. Prostate-specific antigen recurrence-free survival significantly (P = 0.0001) decreased with decline of mast cell density showing poorest outcome for patients without intratumoral mast cells. In multivariate analysis mast cell density narrowly missed to add independent prognostic information (P = 0.0815) for prostate-specific antigen recurrence.

CONCLUSION

High intratumoral mast cell density is associated with favorable tumor characteristics and good prognosis in prostate cancer. This finding is consistent with a role of mast cells in the immunological host-defense reaction on prostate cancer. Triggering mast cell activity might expand immunotherapeutic strategies in prostate cancer.

Predictive value of prostate-specific antigen expression in prostate cancer: a tissue microarray study

OBJECTIVES

To evaluate the prognostic potential of prostate-specific antigen (PSA) expression in tumor specimens in a large cohort of prostate cancers treated by prostatectomy. Although serum PSA measurement has been established as a diagnostic and prognostic tool in prostate cancer, no larger studies have been done of the prognostic potential of this parameter.

METHODS

We used a tissue microarray containing samples of 3261 prostatectomy specimens. PSA expression was scored after immunohistochemical staining on a scale from 0 (absent) to 3 (strong) by an investigator unaware of all other variables. The results were correlated with the pre- and postoperative clinical and pathologic parameters and follow-up data.

RESULTS

Of 2556 eligible tumors, PSA expression was strong in 48.0%, moderate in 36.7%, weak in 12.2%, and absent in 3.1%. The loss of PSA expression correlated significantly with a greater Gleason score, the presence of extraprostatic extension, and a peripheral zone prostate cancer location. It was also significantly associated with PSA recurrence after prostatectomy on univariate analysis but not on multivariate analysis containing the pathologic parameters of the prostatectomy specimens. In the subsets of patients with a preoperative PSA value <6 ng/mL or biopsy Gleason score of 3 + 4, the loss of PSA expression in tissue microarray spots was significantly associated with nonorgan-confined disease.

CONCLUSIONS

The results of our study have shown that the loss of PSA expression in tissue samples of prostate cancer is associated with adverse pathologic features and clinical outcome but is not an independent prognostic factor for PSA recurrence after prostatectomy. However, in the biopsy scenario and in subgroups of patients, it might be a useful parameter for predicting extraprostatic tumor extension.

Distinct subcellular expression patterns of neutral endopeptidase (CD10) in prostate cancer predict diverging clinical courses in surgically treated patients

PURPOSE

Neutral endopeptidase (CD10), an ectopeptidase bound to the cell surface, is thought to be a potential prognostic marker for prostate cancer.

EXPERIMENTAL DESIGN

Prostate cancer patients (N = 3,261) treated by radical prostatectomy at a single institution were evaluated by using tissue microarray. Follow-up data were available for 2,385 patients. The cellular domain (membranous, membranous-cytoplasmatic, and cytoplasmatic only) of CD10 expression was analyzed immunohistochemically and correlated with various clinical and histopathologic features of the tumors.

RESULTS

CD10 expression was detected in 62.2% of cancer samples and occurred preferentially in higher Gleason pattern (P < 0.0001). CD10 expression positively correlated with adverse tumor features such as elevated preoperative prostate-specific antigen (PSA), higher Gleason score, and advanced stage (P < 0.0001 each). Survival analyses showed that PSA recurrence was significantly associated with the staining pattern of CD10 expression. Outcome significantly declined from negative over membranous, membranous-cytoplasmatic, to exclusively cytoplasmatic CD10 expression (P < 0.0001). In multivariate analysis, CD10 expression was an independent predictor for PSA failure (P = 0.0343).

CONCLUSIONS

CD10 expression is an unfavorable independent risk factor in prostate cancer. The subcellular location of CD10 protein is associated with specific clinical courses, suggesting an effect on different important biological properties of prostate cancer cells. The frequent expression of CD10 in prostate cancer and the strong association of CD10 with unfavorable tumor features may qualify this biomarker for targeted therapies.

Molecular staging of prostate cancer in the year 2007

Numerous attempts towards improving patient management by molecular staging have been fruitless so far. No single molecular parameter is routinely analyzed in prostate cancer tissue. This may be partly due to genuine properties of prostate cancer that may make this tumor a difficult target. Furthermore, inherent logistical problems result in a shortage of prostate cancer tissue for research purposes. For the future, it can be hoped that the availability of more powerful molecular techniques in combination with better tissue archives will allow more rapid progress. Powerful DNA array and proteomics methods allow the systematic analysis of virtually all genes of a cancer on the DNA, RNA, and protein level. Although such approaches are sometimes labeled as "fishing expeditions," it cannot be totally disregarded that the simultaneous analysis of all genes has a high likelihood of identifying significant new information. In future, one of the major scientific challenges will be the validation of several potential biomarkers in large enough and clinically well-characterized patient cohorts. In particular, studies on needle core biopsies and hormone refractory cancers are imperatively needed for investigating the natural history of the disease or to discover potential predictive markers for radiation therapy and new therapeutic target genes to answer the clinically most important questions for optimal clinical decision making in prostate cancer patients: which patients will not require local therapy? If local therapy is needed, what is the treatment of choice? What medications should be given if metastases are present?

Close association between HER-2 amplification and overexpression in human tumors of non-breast origin

The relationship between HER-2 overexpression and gene amplification is well evaluated in breast cancers but remains unclear or controversial in many other tumor entities. Therefore, we tested the HER-2 status in more than 120 different tumor entities. 5751 tumor samples were analyzed on TMAs by immunohistochemistry (Hercept-Test, DAKO) and fluorescence in situ hybridization (PathVysion, Abbott-Vysis) under highly standardized conditions. HER-2 overexpression (score 2/3+) and amplification occurred most often in breast cancers but was also seen in 18 other tumor entities including cancers of the urinary bladder (amplification in 14.3%, overexpression in 6.7%), stomach (8.3/4.9%), endometrium (6.6/6.8%), lung (2.8/3.1%) and ovary (2.3/1.2%). Remarkably, a strong association between overexpression and amplification was seen in all examined cancer entities. Trastuzumab therapy is highly efficient in HER-2 amplified breast cancer both in metastatic disease and as an adjuvant therapy. A variety of other tumor entities including frequent neoplasms and cancers with often limited therapeutic options have similar patterns of HER-2 alterations as observed in breast cancer (ie high overexpression due to high level gene amplification). Such tumor entities should be carefully evaluated for a possible utility of trastuzumab treatment.

E2F3 is the main target gene of the 6p22 amplicon with high specificity for human bladder cancer

Amplification of 6p22 occurs in about 10-20% of bladder cancers and is associated with enhanced tumour cell proliferation. Candidate target genes for the 6p22 amplicon include E2F3 and the adjacent gene NM_017774. To clarify which gene is representing the main target, we compared the prevalence of the amplification and the functional role of both genes. Amplification of E2F3 and NM_017774 was analysed by fluorescence in situ hybridization on a bladder cancer tissue microarray composed of 2317 cancer samples. Both genes showed amplification in 104 of 893 (11.6%) interpretable tumours and were exclusively found co-amplified. Additional gene expression analysis by real-time polymerase chain reaction in 12 tumour-derived cell lines revealed that amplification of 6p22 was always associated with co-overexpression of E2F3 and NM_017774. Furthermore, RNA interference was used to study the influence of reduced gene expression on cell growth. In tumour cells with and without the 6p22 amplicon, knockdown of E2F3 always lead to unequivocal reduction of proliferation, whereas knockdown of NM_017774 was only capable to slow down cell proliferation in non-amplified cells. Our findings point out that E2F3 but not NM_017774 is driving enhanced proliferation of 6p22 amplified tumour cells. We conclude that E2F3 must be responsible for the growth advantage of 6p22 amplified bladder cancer cells.

HER2, TOP2A, CCND1, EGFR and C-MYC oncogene amplification in colorectal cancer

AIM

Recent studies had suggested substantial molecular differences between tumours from different ethnic groups. In this study, the molecular differences between the incidences of colorectal carcinoma in Saudi and Swiss populations are investigated.

METHOD

518 cases of colon cancer tumours (114 from Saudi Arabia and 404 from Switzerland) were analysed in a tissue microarray format. Fluorescence in situ hybridisation (FISH) was used to estimate frequencies of copy number changes of known oncogenes, including HER2, TOPO2A, CCND1, EGFR and C-MYC.

RESULTS

Using FISH, amplifications were mostly low level (gene-to-centromere ratio 2 to 4), which is in contrast with other tumour types with more frequent gene amplifications. The amplifications were particularly frequent for MYC (Saudi 9% and Swiss 14.2%) but unrelated to clinical outcome and pathological information. Remarkably, there were four tumours exhibiting classic high-level gene amplification for HER2 (Swiss 1.3%), a pattern often accompanied by response to trastuzumab (Herceptin) in breast cancer. Occasional high-level amplifications were also observed for CCND1 (Saudi 1/106, 0.9%; Swiss 2/373, 0.5%) and EGFR (Swiss 2/355; 0.6%).

CONCLUSIONS

Rare high-level amplifications of therapeutic target genes were found in patients with colon cancer. Although no molecular differences were found between incidences of colon cancer cases in Swiss and Saudi populations, these observations emphasise the urgent need for clinical studies investigating the effect of targeted therapies.

Comprehensive analysis of the expression of the metastasis-associated gene 1 in human neoplastic tissue

CONTEXT

The metastasis-associated gene 1 (MTA1) is overexpressed in several human cancers. Recent reports suggest that MTA1 may play a role in cancer progression either through transcription repression and/or hormone receptor interactions.

OBJECTIVE

To analyze MTA1 expression levels in a wide variety of human tumors.

DESIGN

We used Oncomine, an Internet-based compendium of expression array data, to query more than 90 expression array studies, and we evaluated tissue microarrays composed of more than 3200 samples representing 138 different localized neoplasms.

RESULTS

Both analyses show that MTA1 is ubiquitously expressed in benign and malignant tumors. The highest levels of MTA1 expression were observed in diffuse B-cell lymphoma (mean staining intensity, 3.9/4), basal cell carcinomas (3.7/4), and consistently in tumors of neuroendocrine descent such as paraganglioma (3.7/4) and carcinoid tumor (3.1/4).

CONCLUSIONS

This study characterizes MTA1 expression for the first time across a broad spectrum of primary tumors, demonstrating expression in both benign and malignant neoplasms in addition to showing an association with neuroendocrine differentiation. We also found evidence that MTA1 expression is associated with tissue invasion but may not be sufficient for the progression to metastatic stages.

Nuclear and cytoplasmic Maspin expression in primary non-small cell lung cancer

AIM

To investigate whether nuclear and cytoplasmic Maspin expression is associated with distinct clinicopathological parameters and TP53 expression in a representative series of primary non-small cell lung cancer (NSCLC).

METHODS

Tissue microarrays (n=487) were used to immunohistochemically analyse expression of Maspin and TP53. Cytoplasmic and nuclear expression of Maspin was scored on the basis of the percentage of positive tumour cells. Univariate analysis of clinicopathological variables potentially affecting tumour-specific survival was performed.

RESULTS

Immunohistochemical Maspin expression (nuclear and cytoplasmic) was informative in 72.3% (352/487) of cases. Cytoplasmic and nuclear Maspin immunoreactivity in >or=10% of tumour cells was detected in 37.8% (133/352) and 65.3% (230/352) of informative cases, respectively. Nuclear and cytoplasmic Maspin staining was observed more frequently in primary squamous cell carcinomas than in other lung cancer types. Only nuclear Maspin immunoreactivity was significantly associated with positive TP53 staining. Cytoplasmic or nuclear Maspin expression was not associated with tumour-specific survival.

CONCLUSION

Maspin expression was found both in the nucleus and the cytoplasm of NSCLC, more frequently in squamous cell carcinomas. However, no association with tumour-specific survival could be demonstrated.

Epithelial growth factor receptor status in primary and recurrent ovarian cancer

Success of epidermal growth factor receptor (EGFR) targeting agents in different cancer types is related to EGFR gene mutations and/or copy number gains. We investigated the EGFR gene status and protein expression by DNA mutational analysis, fluorescence in situ hybridization (FISH), and immunohistochemistry in tumor tissues from 80 patients with primary and corresponding recurrent ovarian serous carcinomas. The patients were classified into six groups with ascending EGFR gene copy numbers. EGFR amplification and high polysomy (FISH+) was present in a significant fraction of the primary (20%) and recurrent (22%) ovarian carcinomas. On mutational analysis, only one tumor with a silent EGFR mutation was observed, and this was the only carcinoma with high-level amplification. EGFR protein immunoexpression was seen in 28% of primary and 33% of recurrent carcinomas and correlated to amplification in the primary tumors (P = 0.003). In recurrent carcinoma, moderate and strong EGFR expression was associated with amplification (P = 0.034). These molecular events potentially have impact on the responsiveness to EGFR targeting agents in ovarian cancer.

Increased Apolipoprotein Deposits in Early Atherosclerotic Lesions Distinguish Symptomatic From Asymptomatic Patients

OBJECTIVE

Apolipoprotein E (apoE) and apolipoprotein B100 (apoB) are both involved in receptor-mediated uptake of atherogenic lipoproteins by the liver. Inefficient hepatic clearance of these lipoproteins leads to symptomatic atherosclerosis. Using arterial tissue microarrays, we tested the hypothesis that apoE and apoB accumulation in the arterial wall discriminates between patients with symptomatic atherosclerosis and patients who never experienced cardiovascular events.

METHODS AND RESULTS

In a postmortem study involving 49 patients (22 patients with symptomatic atherosclerosis), we quantified apolipoprotein deposits in arterial rings obtained from the left main coronary, the common carotid, the common iliac, and the renal artery applying tissue microarray technology and semiquantitative immunohistochemistry. In early atherosclerotic lesions, even before atheroma appeared, symptomatic patients had significantly more arterial apoE and apoB deposits than patients without cardiovascular events (P<0.001). Among the symptomatic patients, those without diabetes had more intense apolipoprotein deposits than diabetics. Large amounts of apoE and apoB were found in advanced atherosclerotic lesions, regardless of the activity of the disease.

CONCLUSIONS

Increased apolipoprotein deposits are an early sign of symptomatic atherosclerosis. They may reflect either enhanced retention of atherogenic lipoproteins or impaired local apolipoprotein degradation. The arterial lipoprotein turnover may be different in diabetic patients.

Tissue microarrays for comparing molecular features with proliferation activity in breast cancer

Tissue microarrays (TMAs) are potentially suited to find associations between molecular features and clinical outcome. Enhanced cell proliferation, as measured by Ki67 immunohistochemistry, is related to poor patient prognosis in many different tumor types. Ki67 expression shows considerable intratumoral heterogeneity. It is unclear if the TMA format is suitable for the analysis of potentially heterogeneous markers because of the small size of TMA spots. We have analyzed a breast cancer TMA containing 2,517 breast tissues, including 2,222 neoplastic and 295 normal or premalignant samples, for Ki67 labeling index (Ki67 LI) and additional markers with a known relationship to Ki67 LI by immunohistochemistry (ER, PR, Bcl-2, Egfr, p16, p53) and Fluorescence in situ hybridization (HER2, MDM2, CCND1, MYC). A high Ki67 LI was linked to tumor phenotype including grade (p < 0.0001), stage (p < 0.0001), nodal stage (p = 0.0018), and patient prognosis (p < 0.0001), elevated protein levels of p53, p16 and Egfr, reduced levels of Bcl2, ER, and PR (p < 0.0001 each), as well as amplifications of HER2, MYC, CCND1 and MDM2 (p < 0.0001 each). In summary, all expected associations between Ki67 and the analyzed molecular markers could be reproduced with high statistical significance using a TMA containing only one tissue sample per tumor, measuring 0.6 mm in diameter. We conclude that associations with cell proliferation can be reliably analyzed in a TMA format.

EphB2 expression across 138 human tumor types in a tissue microarray: high levels of expression in gastrointestinal cancers

PURPOSE

To comprehensively evaluate ephrin receptor B2 (EphB2) expression in normal and neoplastic tissues. EphB2 is a tyrosine kinase recently implicated in the deregulation of cell-to-cell communication in many tumors.

EXPERIMENTAL DESIGN

EphB2 protein expression was analyzed by immunohistochemistry on tissue microarrays that included 76 different normal tissues, >4,000 samples from 138 different cancer types, and 1,476 samples of colon cancer with clinical follow-up data.

RESULTS

We found most prominent EphB2 expression in the intestinal epithelium (colonic crypts) with cancer of the colorectum displaying the highest EphB2 positivity of all tumors. Positivity was found in 100% of 118 colon adenomas but in 33.3% of 45 colon carcinomas. EphB2 expression was also observed in 75 tumor categories, including serous carcinoma of the endometrium (34.8%), adenocarcinoma of the esophagus (33.3%), intestinal adenocarcinoma of the stomach (30.2%), and adenocarcinoma of the small intestine (70%). The occasional finding of strong EphB2 positivity in tumors without EphB2 positivity in the corresponding normal cells [adenocarcinoma of the lung (4%) and pancreas (2.2%)] suggests that deregulation of EphB2 signaling may involve up-regulation of the protein expression. In colon carcinoma, loss of EphB2 expression was associated with advanced stage (P < 0.0001) and was an indicator of poor overall survival (P = 0.0098).

CONCLUSIONS

Our results provide an overview on the EphB2 protein expression in normal and neoplastic tissues. Deregulated EphB2 expression may play a role in several cancer types with loss of EphB2 expression serving as an indicator of the possible pathogenetic role of EphB2 signaling in the maintenance of tissue architecture of colon epithelium.

Diagnostic Evaluation of HER-2 as a Molecular Target: An Assessment of Accuracy and Reproducibility of Laboratory Testing in Large, Prospective, Randomized Clinical Trials

PURPOSE

To critically assess the accuracy and reproducibility of human epidermal growth factor receptor type 2 (HER-2) testing in outside/local community-based hospitals versus two centralized reference laboratories and its effect on selection of women for trastuzumab (Herceptin)-based clinical trials.

EXPERIMENTAL DESIGN

Breast cancer specimens from 2,600 women were prospectively evaluated by fluorescence in situ hybridization (FISH) for entry into Breast Cancer International Research Group (BCIRG) clinical trials for HER-2-directed therapies.

RESULTS

HER-2 gene amplification by FISH was observed in 657 of the 2,502 (26%) breast cancers successfully analyzed. Among 2,243 breast cancers with central laboratory immunohistochemistry (10H8-IHC) analysis, 504 (22.54%) showed overexpression (2+ or 3+). Outside/local laboratories assessed HER-2 status by immunohistochemistry in 1,536 of these cases and by FISH in 131 cases. Overall, the HER-2 alteration status determined by outside/local immunohistochemistry showed a 79% agreement rate [kappa statistic, 0.56; 95% confidence interval (95% CI), 0.52-0.60], with FISH done by the central laboratories. The agreement rate comparing BCIRG central laboratory 10H8-IHC and outside/local laboratory immunohistochemistry was 77.5% (kappa statistic, 0.51; 95% CI, 0.46-0.55). Finally, HER-2 status, determined by unspecified FISH assay methods at outside/local laboratories, showed a 92% agreement rate (kappa statistic, 0.83; 95% CI, 0.73-0.93), with FISH done at the BCIRG central laboratories.

CONCLUSIONS

Compared with the HER-2 status determined at centralized BCIRG reference laboratories, these results indicate superiority of FISH to accurately and reproducibly assess tumors for the HER-2 alteration at outside/local laboratories for entry to clinical trials.

Predominance of high-grade pathway in breast cancer development of Middle East women

Recent data have suggested considerable molecular differences in cancers from various ethnical groups. As molecular features are increasingly used for predicting cancer prognosis and response to therapy, better knowledge of ethnic molecular features is important. To identify potential molecular differences between breast cancers in Europe and the Middle East, we analyzed consecutive breast cancer series from Switzerland (n=2197) and Saudi Arabia (n=204). Tissue microarrays were analyzed by fluorescence in situ hybridization for HER2, CCND1, MYC, and EGFR amplification. The data revealed marked differences between Saudi and Swiss patients. Saudi breast cancers had a markedly higher frequency of HER2 (31 vs 17%; P<0.0001) and MYC (16 vs 5%; P<0.0001) amplifications than Swiss breast cancers. Remarkably, this was partly due to a much higher incidence of grade 3 cancers in the Saudi than in the Swiss population (65 vs 32%; P<0.0001). However, differences in amplification frequency hold also true within grade 3 cancers (HER2: 40 vs 30%, P<0.05; MYC: 22 vs 11%, P=0.002). Interestingly, in combination with known age standardized incidence rates of breast cancer in Saudi Arabia (21.6/100 000) and Switzerland (70.1/100 000), these data suggest that the incidence of high-grade breast cancer is comparable for Saudi and Swiss women, while the incidence of low-grade breast cancers is about 14 times lower in Saudi than for Swiss women. These observations suggest that a difference in genetic susceptibility and/or lifestyle between Saudi and Swiss women has a substantial and much higher than expected impact on the risk of low-grade breast cancer.

Prognostic relevance of gene amplifications and coamplifications in breast cancer

Multiple different oncogenes have been described previously to be amplified in breast cancer including HER2, EGFR, MYC, CCND1, and MDM2. Gene amplification results in oncogene overexpression but may also serve as an indicator of genomic instability. As such, presence of one or several gene amplifications may have prognostic significance. To assess the prognostic importance of amplifications and coamplifications of HER2, EGFR, MYC, CCND1, and MDM2 in breast cancer, we analyzed a breast cancer tissue microarray containing samples from 2197 cancers with follow-up information. Fluorescence in situ hybridizations revealed amplifications of CCND1 in 20.1%, HER2 in 17.3%, MDM2 in 5.7%, MYC in 5.3%, and EGFR in 0.8% of the tumors. All gene amplifications were significantly associated with high grade. HER2 (P < 0.001) and MYC amplification (P < 0.001) were also linked to shortened survival. In case of HER2, this was independent of grade, pT, and pN categories. MYC amplification was almost 3 times more frequent in medullary cancer (15.9%), than in the histologic subtype with the second highest frequency (ductal; 5.6%; P = 0.0046). HER2 and MYC amplification were associated with estrogen receptor/progesterone receptor negativity (P < 0.001) whereas CCND1 amplification was linked to estrogen receptor/progesterone receptor positivity (P < 0.001). Coamplifications were more prevalent than expected based on the individual frequencies. Coamplifications of one or several other oncogenes occurred in 29.6% of CCND1, 43% of HER2, 55.7% of MDM2, 65% of MYC, and 72.8% of EGFR-amplified cancers. HER2/MYC-coamplified cancers had a worse prognosis than tumors with only one of these amplifications. Furthermore, a gradual decrease of survival was observed with increasing number of amplifications. In conclusion, these data support a major prognostic impact of genomic instability as determined by a broad gene amplification survey in breast cancer.

Expression patterns of potential therapeutic targets in prostate cancer

Androgen withdrawal is the only effective therapy for patients with advanced prostate cancer, but progression to androgen independence ultimately occurs in almost all patients. Novel therapeutic strategies targeting molecular mechanisms that mediate resistance to hormonal and chemotherapeutic treatment are highly warranted. Here, we aimed to evaluate the expression of potential therapeutic targets in advanced prostate cancer. A tissue microarray (TMA) containing samples from 535 tissue blocks was constructed, including benign prostatic hyperplasia as controls (n = 65), prostatic intraepithelial neoplasia (PIN; n = 78), clinically localized prostate cancers (n = 181), as well as hormone-refractory local recurrences (n = 120) and distant metastases (n = 91). The expression of 13 different proteins was analyzed using immunohistochemistry (Bcl-2, p53, ILK, Syndecan-1, MUC-1, EGFR, HER2/neu, HSP-90, Ep-CAM, MMP-2, CD-10, CD-117 and Ki67). Significant overexpression in hormone-refractory prostate cancer and metastatic tissue compared to localized prostate cancer was found for Ki67 (64% vs. 9%), Bcl-2 (11% vs. 1%), p53 (35% vs. 4%), Syndecan-1 (38% vs. 3%), EGFR (16% vs. 1%) and HER2/neu (16% vs. 0%). Overexpression of CD-117 was restricted to 1 single metastasis. All other markers did not show relevant differences in expression between subgroups. Taken together, p53, Bcl-2, Syndecan-1, EGFR and HER2/neu are preferentially expressed in hormone-refractory and metastatic prostate cancer. Selected inhibition of these targets might offer a strategy to treat advanced tumors and prevent further progression. Treatment decisions should not be based on findings in primary tumors but rather on tissues from recurrent or metastatic lesions.

Tissue microarrays

New high-throughput screening technologies have led to the identification of hundreds of genes with potential roles in cancer or other diseases. For evaluation of promising candidate genes, however, in-situ analysis of high numbers of clinical tissue samples is mandatory. The tissue microarray (TMA) technology greatly facilitates such analysis. In this method minute tissue samples (0.6 mm in diameter) from up to 1000 different tissues can be analyzed on one microscope glass slide. All in-situ methods suitable for histological studies can be applied to TMAs without major changes in protocols, including immunohistochemistry, fluorescence in-situ hybridization, or RNA in-situ hybridization. Because all tissues are analyzed simultaneously with the same batch of reagents, TMA studies provide an unprecedented degree of standardization, speed, and cost efficiency.

High Ep-CAM expression is associated with poor prognosis in node-positive breast cancer

Previous studies in small series of patients with invasive breast cancer suggested a prognostic value of Ep-CAM overexpression in primary tumor tissue. To corroborate these findings, we performed a retrospective analysis of Ep-CAM expression using a tissue microarray containing tissue specimens from a large patient set. Ep-CAM expression was evaluated by immunohistochemistry in breast cancer tissue from 1715 patients with documented raw survival data. High level Ep-CAM expression (overexpression) was found in 41.7% of tumor samples, low level expression was found in 48.0% and no expression in 10.3% of tumor samples. Ep-CAM expression predicted poor overall survival in this patient cohort (p < 0.0001). Overall survival decreased significantly with increasing Ep-CAM expression. However, in this patient sample Ep-CAM expression was not an independent prognostic marker by multivariate analysis. Subgroup analysis revealed that Ep-CAM expression was a prognostic marker in node-positive (p < 0.0001) but not in node-negative (p = 0.58) breast cancer patients. Intriguingly, Ep-CAM expression was predictive for a dismal prognosis in patients receiving adjuvant cytotoxic (p = 0.03) or hormonal therapy (p < 0.0001) but not in untreated patients (p = 0.41). In summary, this study provides strong evidence that expression of Ep-CAM is a powerful marker of poor prognosis in node-positive invasive breast carcinoma and a potential predictive marker of sensitivity to adjuvant hormonal and/or cytotoxic treatment modalities.

Hepatocyte paraffin 1 expression in human normal and neoplastic tissues: tissue microarray analysis on 3,940 tissue samples

Hepatocyte paraffin 1 (Hep Par 1) is a monoclonal antibody developed from hepatic tissue from a failed liver allograft. Several studies have shown that Hep Par 1 is a useful marker to differentiate hepatocellular carcinoma (HCC) from other types of adenocarcinoma metastatic to the liver. The aim of our study was the systematic investigation of the epidemiology of Hep Par 1 expression in 3,940 tissue samples using the tissue microarray technique. Strong Hep Par 1 expression was found most frequently in 35 (73%) of 48 HCCs. In nonhepatic tumors, strong Hep Par 1 expression was detected in adenocarcinoma of the lung (2/50), gallbladder (3/31), pancreas (2/48), stomach (3/74), small intestine (1/11), adenoma of the colon with high-grade dysplasia (1/49), adrenal gland carcinoma (1/6), paraganglioma (1/9), and malignant melanoma (2/48). Our data suggest that Hep Par 1 is a highly specific marker for HCC, although several nonhepatic tumors occasionally can show some Hep Par 1 positivity.

Hepatocyte paraffin 1 expression in human normal and neoplastic tissues: tissue microarray analysis on 3,940 tissue samples

Hepatocyte paraffin 1 (Hep Par 1) is a monoclonal antibody developed from hepatic tissue from a failed liver allograft. Several studies have shown that Hep Par 1 is a useful marker to differentiate hepatocellular carcinoma (HCC) from other types of adenocarcinoma metastatic to the liver. The aim of our study was the systematic investigation of the epidemiology of Hep Par 1 expression in 3,940 tissue samples using the tissue microarray technique. Strong Hep Par 1 expression was found most frequently in 35 (73%) of 48 HCCs. In nonhepatic tumors, strong Hep Par 1 expression was detected in adenocarcinoma of the lung (2/50), gallbladder (3/31), pancreas (2/48), stomach (3/74), small intestine (1/11), adenoma of the colon with high-grade dysplasia (1/49), adrenal gland carcinoma (1/6), paraganglioma (1/9), and malignant melanoma (2/48). Our data suggest that Hep Par 1 is a highly specific marker for HCC, although several nonhepatic tumors occasionally can show some Hep Par 1 positivity.

Prevalence of KIT expression in human tumors

PURPOSE

KIT is a target for imatinib mesylate (Gleevec; Novartis Pharma, Basel, Switzerland). Gastrointestinal stromal tumors (GISTs) express KIT and respond favorably to imatinib therapy. To determine other tumors in which such a molecular targeted therapy might be indicated, we investigated KIT expression in different human tumor types. Because recent studies in GISTs suggest that KIT-activating mutations predict response to imatinib therapy, we also sequenced a subset of positive tumors.

MATERIALS AND METHODS

More than 3,000 tumors from more than 120 different tumor categories were analyzed by immunohistochemistry in a tissue microarray format. Seven commercially available anti-KIT antibodies were initially evaluated. The antibody A4502 (DAKO) was selected for analysis because of a high frequency of positivity in GIST and low staining background in other tissues. To determine the frequency of KIT mutations in various tumor types, the exons 2, 8, 9, 11, 13, and 17 (where mutations previously were reported) were sequenced in 36 tumors with strong KIT expression.

RESULTS

KIT positivity was detected in 28 of 28 GISTs (100%), 42 of 50 seminomas (84%), 34 of 52 adenoid-cystic carcinomas (65%), 14 of 39 malignant melanomas (35%), and eight of 47 large-cell carcinomas of the lung (17%), as well as in 47 additional tumor types. KIT mutations were found in six of 12 analyzed GISTs, but only in one of 24 other tumors.

CONCLUSION

The results suggest that KIT expression occurs infrequently in most tumor types and that, with the exception of GISTs, KIT gene mutations are rare in immunohistochemically KIT-positive tumors.

HER2 analysis in breast cancer: reduced immunoreactivity in FISH non-informative cancer biopsies

Due to the central role in predicting response to herceptin and possibly also other anticancer drugs, accurate and reproducible detection of the HER2 status is important. Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) are the most commonly used methods for HER2 analysis. It is a disadvantage of FISH that a fraction of cases remain not interpretable probably due to suboptimal tissue handling before analysis. To investigate a possible influence of tissue damage on the results of HER2 IHC we compared the HER2 IHC results obtained in tumors with and without interpretable FISH in a breast cancer tissue microarray. The HER2 IHC results differed greatly between 1551 tumors with interpretable HER2 FISH signals and 405 breast cancers showing no FISH signals. FISH informative tumors had an IHC score of 3+ in 12.6%, 2+ in 3% and 1+ in 9.2% of cases. FISH non-informative tumors showed significantly lower IHC scores (p < 0.0001). They were IHC 3+ in 3.9%, 2+ in 3.7% and 1+ in 4.4% of cases. Overall, the data show that not only FISH but also IHC results are dependent on good tissue quality for successful analysis. Poor tissue quality can be easily identified in FISH analyses because of a lack of hybridization signals. Inappropriate tissue handling is more dangerous in IHC because an artificial lack of staining can be regarded as 'negative' result.

Expression and amplification of therapeutic target genes in retinoblastoma

PURPOSE

We set out to evaluate alterations of the therapeutic target genes KIT (CD 117), EGFR, and HER-2 in human retinoblastoma.

METHODS

Ninety-five formalin-fixed, paraffin-embedded retinoblastomas were brought into a tissue microarray (TMA) format. Immunohistochemistry was performed to analyze the expression of CD117, EGFR, and HER-2. Fluorescence in situ hybridization (FISH) was utilized for detection of EGFR amplifications. Three tumors with strong CD117 positivity were sequenced for KIT exon 11 mutations.

RESULTS

Detectable CD117 expression was seen in 19% of all interpretable cases. Sequence analysis of the three tumors with the strongest CD117 expression revealed no mutations. EGFR was positive in 14% of all cases. No EGFR amplification was observed by FISH, however. All tumors were negative for HER-2 expression.

CONCLUSIONS

Our data suggest that selected cases of retinoblastoma may be candidates for anti-EGFR and imatinib mesylate (STI571) therapy.

Arterial Neovascularization and Inflammation in Vulnerable Patients

Background— Atherosclerosis is complicated by cardiovascular events such as myocardial infarction, stroke, or peripheral arterial occlusive disease. Inflammation and pathological neovascularization are thought to precipitate plaque rupture or erosion, both causes of arterial thrombosis and cardiovascular events. We tested the hypothesis that arterial inflammation and angiogenic events are increased throughout the arterial tree in vulnerable patients, ie, in patients who suffered from cardiovascular events, compared with patients who never suffered from complications of atherosclerosis.

Methods and Results— In a postmortem study, we quantified the inflammatory infiltrate and microvascular network in the arterial wall of iliac, carotid, and renal arteries. Tissue microarray technology was adapted to investigate full-thickness arterial sectors. We compared 22 patients with symptomatic atherosclerosis with 27 patients who never had suffered from any cardiovascular event. The absolute intimal macrophage content was 2- to 4-fold higher in vulnerable patients at all 3 arterial sites analyzed ( P <0.05). Patients with symptomatic atherosclerosis had a denser network of vasa vasorum than patients with asymptomatic disease (33±2 versus 25±2 adventitial microvessels per 1 mm 2 ; P =0.008). Hyperplasia of vasa vasorum was an early and macrophage infiltration was a late sign of symptomatic atherosclerosis.

Conclusions— High intimal macrophage content and a hyperplastic network of vasa vasorum characterize vulnerable patients suffering from symptomatic atherosclerosis. These changes are uniformly present in different arterial beds and support the concept of symptomatic atherosclerosis as a panarterial disease.

Influence of slide aging on results of translational research studies using immunohistochemistry

Several reports have shown that a long delay between cutting sections and immunohistochemical (IHC) staining can decrease the IHC reaction intensity. However, systematic large-scale studies to investigate to what extent this problem may influence the outcome of translational research studies are lacking. In this study, we used a tissue microarray (TMA) approach to investigate the influence of slide age on comparisons between the results of IHC analyses for estrogen receptor (ER), progesterone receptor (PR), cyclin D1, HER2 (HercepTest), and E-cadherin and clinical outcome in a series of 522 breast cancer patients. Old TMA sections stored for 6 months at 4 degrees C and freshly cut sections were analyzed under exactly identical experimental conditions. As compared to results obtained on freshly cut sections, the frequency of positivity on old sections decreased from 65 to 46% for ER (P<0.0001), from 33 to 18.5% for PR (P<0.0001), from 16.3 to 9.6% for HER2 (P=0.0047), from 45.1 to 37.7% for cyclin D1 (P=0.10), and from 58.9 to 32.9% for E-cadherin (P<0.0001). Despite the lower fraction of positive cases, most associations between IHC data and tumor phenotype that were observed in fresh section analysis were also found when old section data were analyzed. The results confirm that slide aging has a great influence on the intensity of IHC staining in individual cases, but they also suggest that many clinicopathological associations can be detected if suboptimally processed sections are used for IHC.

The homeobox intestinal differentiation factor CDX2 is selectively expressed in gastrointestinal adenocarcinomas

CDX2 is a homeobox domain-containing transcription factor that is important in the development and differentiation of the intestines. Based on recent studies, CDX2 expression is immunohistochemically detectable in normal colonic enterocytes and is retained in most, but not all, colorectal adenocarcinomas. CDX2 expression has also been documented in a subset of adenocarcinomas arising in the stomach, esophagus and ovary. In this study, we examined CDX2 expression in a series of large tissue microarrays representing 4652 samples of normal and neoplastic tissues. Strong nuclear staining for CDX2 was observed in 97.9% of 140 colonic adenomas, 85.7% of 1109 colonic adenocarcinomas overall and 81.8% of 55 mucinous variants. There was no significant difference in the staining of well-differentiated (96%) and moderately differentiated tumors (90.8%, P=0.18), but poorly differentiated tumors showed reduced overall expression (56.0%, P<0.000001). Correspondingly, there was an inverse correlation between CDX2 expression and tumor stage, with a significant decrease in staining between pT2 and pT3 tumors (95.8 vs 89.0%, P<0.012), and between pT3 and pT4 tumors (89.0 vs 79.8%, P<0.016). Analysis of 140 locally advanced, CDX2-positive colorectal adenocarcinomas coarrayed with their matching lymph node metastases revealed that expression of this marker was retained in 82.1% of the metastases. Consistent with previous reports, CDX2 staining was observed in gastric adenocarcinomas (n=71), more commonly in the intestinal-type than the diffuse-type (28.9 vs 11.5%, P<0.05). Occasional ovarian carcinomas were positive for CDX2, including mucinous (10.5%), endometrioid (9.3%) and serous variants (2%), but expression was either very rare or absent in primary carcinomas of the lung, breast, thyroid, pancreas, liver, gallbladder, kidney, endometrium and urinary bladder. A low frequency of CDX2 expression in pancreatic and biliary carcinomas observed on the microarrays was pursued further by comparing these tumors with ampullary adenocarcinomas on conventional sections. Ampullary adenocarcinomas were more commonly positive for CDX2 (19/24, 79%) than cholangiocarcinomas (1/11, 9%) and pancreatic carcinomas (3/20, 15%). In summary, CDX2 is a sensitive and specific marker for colorectal adenocarcinoma, although its expression is decreased among higher grade and stage tumors, and it is not invariably present in metastases from positive primaries. CDX2 may also be helpful in distinguishing adenocarcinomas of the ampulla from those arising in the pancreas and biliary tree.

TRIO amplification and abundant mRNA expression is associated with invasive tumor growth and rapid tumor cell proliferation in urinary bladder cancer

Studies by comparative genome hybridization have suggested that 5p amplification is related to tumor progression in urinary bladder cancer. In this study seven genes (TAS2R, ADCY2, DNAH5, CTNND2, TRIO, ANKH, and MYO10) located to 5p15.31-5p15.1 were analyzed by fluorescence in situ hybridization using a tissue microarray containing samples from tumors and cell lines with known 5p amplification by comparative genome hybridization. Amplification frequency was highest for TRIO, which maps to 5p15.2 and encodes a protein with a putative role in cell-cycle regulation. To further investigate the role of TRIO amplification in bladder cancer, a tissue microarray containing samples from 2317 bladder tumors was used for fluorescence in situ hybridization analysis. TRIO amplification was strongly associated with invasive tumor phenotype, high tumor grade, and rapid tumor cell proliferation (Ki67 LI) (P < 0.0001 each). Only 7 of 456 pTaG1/G2 tumors (1.5%) but 62 of 485 pT1-4 carcinomas (12.8%) had TRIO amplification. TRIO amplification was not associated with poor prognosis. Using a frozen bladder tumor tissue microarray RNA in situ hybridization confirmed that TRIO is up-regulated in amplified tumors. It is concluded that TRIO up-regulation through amplification has a potential role in bladder cancer progression.

Tissue microarrays for early target evaluation

Early assessment of the probable biological importance of drug targets, the potential market size of a successful new drug, and possible treatment side effects are critical for risk management in drug development. A comprehensive molecular epidemiology analysis involving thousands of well-characterized human tissues will thus provide vital information for strategic decision-making. Tissue microarray (TMA) technology is ideally suited for such projects. The simultaneous analysis of thousands of tissues enables highly standardized, fast and affordable translational research studies of unprecedented scale.:

Tissue microarrays

The identification of disease-related genes is a major focus of modern biomedical research. Recent techniques, including array-based platforms for molecular profiling of disease tissues such as DNA arrays for expression profiling or matrix comparative genomic hybridization, allow for the comprehensive screening of the whole genome in a single experiment. Consequently, thousands of candidate genes have already been identified that may be linked to disease development and progression, and the process of lead discovery continues unimpeded. The evaluation of the clinical value of such leads is challenging because thousands of well-characterized tissue specimens must be analyzed. Tissue microarray (TMA) technology enables high-throughput tissue analyses to keep pace with the rapid process of lead discovery. With this technique, up to 1000 minute tissue samples are brought into an array format and analyzed simultaneously. The TMA technology is a fast, cost-effective, and statistically powerful method that will substantially facilitate translational research.

Impaired expression of the cell cycle regulator BTG2 is common in clear cell renal cell carcinoma

The prognosis of patients with renal cell carcinoma (RCC) is poor. A full understanding of the molecular genetics and signaling pathways involved in renal cancer development and in the metastatic process is of central importance for developing innovative and novel treatment options. In this study, BD Atlas Human Cancer 1.2 cDNA microarrays were used to identify genes involved in renal tumorigenesis. By analyzing gene expression patterns of four clear cell RCC (cRCC) cell lines and normal renal tissue, 25 genes were found differentially expressed. To determine the relevance of these genes, RNA in situ hybridization was performed on a tissue microarray generated from 61 snap-frozen primary renal cell carcinomas and 12 normal renal cortex biopsies. B-cell translocation gene 2 (BTG2), a negative cell cycle regulator, which was expressed in normal renal tissue but down-regulated in cRCC cell lines and primary cRCCs, was selected for additional experiments. Quantitative BTG2 mRNA expression analysis in 42 primary cRCCs and 18 normal renal cortex biopsies revealed up to 44-fold reduced expression in the tumor tissues. Decrease of BTG2 expression was not associated with tumor stage, grade, and survival. Cell culture experiments demonstrated that BTG2 expression was weakly inducible by the phorbolester 12-O-tetradecanoylphorbol-13-acetate in one of four cRCC cell lines. In contrast, increasing cell density led to elevated BTG2 mRNA expression in three of four cRCC cell lines. In both experiments, BTG2 mRNA levels did not reach values observed in normal renal tissue. These data suggest that down-regulation of BTG2 is an important step in renal cancer development.

Frequent EpCam protein expression in human carcinomas

Expression of the transmembrane glycoprotein EpCam (epithelial cellular adhesion molecule) occurs in normal epithelium of different organs and was described in carcinomas of various sites. Specific anti-EpCam therapies are now being used in clinical trials. Thus, it is of interest to know which tumor types express or overexpress this protein, and in what frequency. We therefore analyzed EpCam expression by immunohistochemistry on a tissue microarray containing 3900 tissue samples of 134 different histological tumor types and subtypes. EpCam expression was detected in 98 of 131 tumor categories. At least a weak EpCam expression in >10% of tumors was observed in 87 of 131 different tumor categories. Adenocarcinomas of the colon (81%) and pancreas (78%), as well as hormone-refractory adenocarcinomas of the prostate (71%), were identified as particularly promising therapy targets with a high fraction of strongly positive tumors. Most soft-tissue tumors and all lymphomas were EpCam negative. It is concluded that anti-EpCam therapies, if proven to be successful, will have broad applications in a wide variety of carcinomas.