Transfer and multiplex immunoblotting of a paraffin embedded tissue

A Novel Quantitative Multiplex Tissue Immunoblotting for Biomarkers Predicts a Prostate Cancer Aggressive Phenotype

BACKGROUND

Early prediction of disease progression in men with very low-risk (VLR) prostate cancer who selected active surveillance (AS) rather than immediate treatment could reduce morbidity associated with overtreatment.

METHODS

We evaluated the association of six biomarkers [Periostin, (-5, -7) proPSA, CACNA1D, HER2/neu, EZH2, and Ki-67] with different Gleason scores and biochemical recurrence (BCR) on prostate cancer TMAs of 80 radical prostatectomy (RP) cases. Multiplex tissue immunoblotting (MTI) was used to assess these biomarkers in cancer and adjacent benign areas of 5 μm sections. Multivariate logistic regression (MLR) was applied to model our results.

RESULTS

In the RP cases, CACNA1D, HER2/neu, and Periostin expression were significantly correlated with aggressive phenotype in cancer areas. An MLR model in the cancer area yielded a ROC-AUC = 0.98, whereas in cancer-adjacent benign areas, yielded a ROC-AUC = 0.94. CACNA1D and HER2/neu expression combined with Gleason score in a MLR model yielded a ROC-AUC = 0.79 for BCR prediction. In the small biopsies from an AS cohort of 61 VLR cases, an MLR model for prediction of progressors at diagnosis retained (-5, -7) proPSA and CACNA1D, yielding a ROC-AUC of 0.78, which was improved to 0.82 after adding tPSA into the model.

CONCLUSIONS

The molecular profile of biomarkers is capable of accurately predicting aggressive prostate cancer on retrospective RP cases and identifying potential aggressive prostate cancer requiring immediate treatment on the AS diagnostic biopsy but limited in BCR prediction.

IMPACT

Comprehensive profiling of biomarkers using MTI predicts prostate cancer aggressive phenotype in RP and AS biopsies.

Recent developments in multiplexing techniques for immunohistochemistry

Methods to detect immunolabeled molecules at increasingly higher resolutions, even when present at low levels, are revolutionizing immunohistochemistry (IHC). These technologies can be valuable for the management and examination of rare patient tissue specimens, and for improved accuracy of early disease detection. The purpose of this article is to highlight recent multiplexing methods that are candidates for more prevalent use in clinical research and potential translation to the clinic. Multiplex IHC methods, which permit identification of at least 3 and up to 30 discrete antigens, have been divided into whole-section staining and spatially-patterned staining categories. Associated signal enhancement technologies that can enhance performance and throughput of multiplex IHC assays are also discussed. Each multiplex IHC technique, detailed herein, is associated with several advantages as well as tradeoffs that must be taken into consideration for proper evaluation and use of the methods.

Proteomic expressional profiling of a paraffin-embedded tissue by multiplex tissue immunoblotting

In the functional proteome era, the proteomic profiling of clinicopathologic annotated tissues is an essential step for mining and evaluations of candidate biomarkers for disease. Previously, application of routine proteomic methodologies to clinical tissue specimens has provided unsatisfactory results. Multiplex tissue immunoblotting is a method of transferring proteins from a formalin-fixed, paraffin-embedded tissue section to a stack of membranes which can be applied to a conventional immunoblotting method. A single tissue section can be transferred to up to ten membranes, each of which is probed with antibodies and detected with fluorescent tags. By this approach, total protein and target signals can be simultaneously determined on each membrane; hence each antibody is internally normalized. Phosphorylation specific antibodies as well as antibodies that do not readily work well with paraffin-embedded tissue are applicable to the membranes, expanding the menu of antibodies that can be utilized with formalin-fixed tissue. This novel platform can provide quantitative detection retaining histomorphologic detail in clinical samples and has great potential to facilitate discovery and development of new diagnostic assays and therapeutic agents.

Multiplexed immunohistochemistry, imaging, and quantitation: a review, with an assessment of Tyramide signal amplification, multispectral imaging and multiplex analysis

Tissue sections offer the opportunity to understand a patient's condition, to make better prognostic evaluations and to select optimum treatments, as evidenced by the place pathology holds today in clinical practice. Yet, there is a wealth of information locked up in a tissue section that is only partially accessed, due mainly to the limitations of tools and methods. Often tissues are assessed primarily based on visual analysis of one or two proteins, or 2-3 DNA or RNA molecules. Even while analysis is still based on visual perception, image analysis is starting to address the variability of human perception. This is in contrast to measuring characteristics that are substantially out of reach of human perception, such as parameters revealed through co-expression, spatial relationships, heterogeneity, and low abundance molecules. What is not routinely accessed is the information revealed through simultaneous detection of multiple markers, the spatial relationships among cells and tissue in disease, and the heterogeneity now understood to be critical to developing effective therapeutic strategies. Our purpose here is to review and assess methods for multiplexed, quantitative, image analysis based approaches, using new multicolor immunohistochemistry methods, automated multispectral slide imaging, and advanced trainable pattern recognition software. A key aspect of our approach is presenting imagery in a workflow that engages the pathologist to utilize the strengths of human perception and judgment, while significantly expanding the range of metrics collectable from tissue sections and also provide a level of consistency and precision needed to support the complexities of personalized medicine.

Assessment of vascular endothelial growth factor in formalin fixed, paraffin embedded colon cancer specimens by means of a well-based reverse phase protein array

BACKGROUND

Vascular endothelial growth factor (VEGF) is a critical pro-angiogenic factor, found in a number of cancers, and a target of therapy. It is typically assessed by immunohistochemistry (IHC) in clinical research. However, IHC is not a quantitative assay and is rarely reproducible. We compared VEGF levels in colon cancer by IHC and a quantitative immunoassay on proteins isolated from formalin fixed, paraffin embedded tissues.

RESULTS

VEGF expression was studied by means of a well-based reverse phase protein array (RPPA) and immunohistochemistry in 69 colon cancer cases, and compared with various clinicopathologic factors. Protein lysates derived from formalin fixed, paraffin embedded tissue contained measurable immunoreactive VEGF molecules. The VEGF expression level of well differentiated colon cancer was significantly higher than those with moderately and poorly differentiated carcinomas by immunohistochemistry (P = 0.04) and well-based RPPA (P = 0.04). VEGF quantification by well-based RPPA also demonstrated an association with nodal metastasis status (P = 0.05). In addition, the normalized VEGF value by well-based RPPA correlated (r = 0.283, P = 0.018). Furthermore, subgroup analysis by histologic type revealed that adenocarcinoma cases showed significant correlation (r = 0.315, P = 0.031) between well-based RPPA and IHC.

CONCLUSIONS

The well-based RPPA method is a high throughput and sensitive approach, is an excellent tool for quantification of marker proteins. Notably, this method may be helpful for more objective evaluation of protein expression in cancer patients.

Tumor profiling using protein biomarker panels in malignant melanoma: application of tissue microarrays and beyond

Despite advances in our knowledge of the disease, malignant melanoma remains an unpredictable entity. The revolution in molecular biological techniques, such as DNA sequencing and gene-expression profiling, has uncovered many potential protein targets and biomarkers relevant to melanoma progression. Successful clinical application would be aided significantly by downstream proteomic validation of those candidate markers using a combination of immunohistochemistry and tissue microarrays. Yet, research in this context seems to lag behind the output of genomic data relating to melanoma. In this article, we look at the strengths and pitfalls of tissue microarrays in malignant melanoma. We will show how tissue microarrays have become a vital step in the transition from molecular techniques to useful clinical assays and interventions and look at likely future developments for advances in this field.

Tissue microarrays as a tool in the discovery and validation of predictive biomarkers

The tissue microarray (TMA) is the embodiment of high-throughput pathology. The platform combines tens to hundreds of tissue samples on a single microscope slide for interrogation with routine molecular pathology tools. TMAs have enabled the rapid and cost-effective screening of biomarkers for diagnostic, prognostic, and predictive utility. Most commonly applied to the field of oncology, the TMA has accelerated the development of new biomarkers, and is emerging as an essential tool in the discovery and validation of tissue biomarkers for use in personalized medicine. This chapter provides an overview of TMA technology and highlights the advantages of using TMAs as tools toward rapid introduction of new biomarkers for clinical use.

The gain in brain: novel imaging techniques and multiplexed proteomic imaging of brain tissue ultrastructure

The rapid accumulation of neuroproteomics data in recent years has prompted the emergence of novel antibody-based imaging methods that aim to understand the anatomical and functional context of the multitude of identified proteins. The pioneering field of ultrastructural multiplexed proteomic imaging now includes a number of high resolution methods, such as array tomography, stimulated emission depletion microscopy, stochastic optical reconstruction microscopy and automated transmission electron microscopy, which allow a detailed molecular characterization of individual synapses and subsynaptic structures within brain tissues for the first time. While all of these methods still face considerable limitations, a combined complementary approach building on the respective strengths of each method is possible and will enable fascinating research into the proteomic diversity of the nervous system.

Tissue microarrays and digital image analysis

Tissue microarrays (TMAs) have recently emerged as very valuable tools for high-throughput pathological assessment, especially in the cancer research arena. This important technology, however, has yet to fully penetrate into the area of toxicology. Here, we describe the creation of TMAs representative of samples produced from conventional toxicology studies within a large-scale, multi-institutional pan-European project, PredTox. PredTox, short for Predictive Toxicology, formed part of an EU FP6 Integrated Project, Innovative Medicines for Europe (InnoMed), and aimed to study pre-clinically 16 compounds of known liver and/or kidney toxicity. In more detail, TMAs were constructed from materials corresponding to the full face sections of liver and kidney from rats treated with different drug candidates by members of the consortium. We also describe the process of digital slide scanning of kidney and liver sections, in the context of creating an online resource of histopathological data.

Antibody-based proteomics: fast-tracking molecular diagnostics in oncology

The effective implementation of personalized cancer therapeutic regimens depends on the successful identification and translation of informative biomarkers to aid clinical decision making. Antibody-based proteomics occupies a pivotal space in the cancer biomarker discovery and validation pipeline, facilitating the high-throughput evaluation of candidate markers. Although the clinical utility of these emerging technologies remains to be established, the traditional use of antibodies as affinity reagents in clinical diagnostic and predictive assays suggests that the rapid translation of such approaches is an achievable goal. Furthermore, in combination with, or as alternatives to, genomic and transcriptomic methods for patient stratification, antibody-based proteomics approaches offer the promise of additional insight into cancer disease states. In this Review, we discuss the current status of antibody-based proteomics and its contribution to the development of new assays that are crucial for the realization of individualized cancer therapy.

Histo-proteomic profiling of formalin-fixed, paraffin-embedded tissue

In the functional proteome era, the proteomic profiling of clinicopathologic-annotated tissues is an essential step for mining and evaluating candidate biomarkers for disease. For many diseases, but especially cancer, the development of predictive biomarkers requires performing assays directly on the diseased tissue. The last decade has seen the explosion of both prognostic and predictive biomarkers in the research setting but few of these biomarkers have entered widespread clinical use. Previously, application of routine proteomic methodologies to clinical formalin-fixed and paraffin-embedded tissue specimens has provided unsatisfactory results. In this paper, we will discuss recent advancements in proteomic profiling technology for clinical applications. These approaches focus on the retention of histomorphologic information as an element of the proteomic analysis.

The expression of phospho-AKT, phospho-mTOR, and PTEN in extrahepatic cholangiocarcinoma

PURPOSE

The protein kinase B (AKT) pathway plays a key role in the regulation of cellular survival, apoptosis, and protein translation, and has been shown to have prognostic significance in a number of cancers. We sought to define its role in extrahepatic cholangiocarcinoma.

EXPERIMENTAL DESIGN

Two hundred twenty-one extrahepatic cholangiocarcinoma patients with clinicopathologic data, including survival, were arrayed into tissue microarrays. Phosphorylated AKT (p-AKT), phosphorylated mammalian target of rapamycin (p-mTOR), and total phosphatase and tensin homolog deleted on chromosome 10 (PTEN) protein expressions were studied with multiplex tissue immunoblotting assay.

RESULTS

Expressions of p-AKT and p-mTOR were significantly increased in extrahepatic cholangiocarcinoma cases compared with normal and dysplastic bile duct epithelium (P < 0.05 both). Decreased PTEN expression was observed in patients with increasing depth of invasion (P < 0.05), T classification (P < 0.05), and stage grouping (P < 0.05), and the presence of invasion of the pancreas (P < 0.05) and duodenum (P < 0.05). Decreased PTEN expression (P = 0.004) as well as decreased PTEN/p-AKT (P = 0.003) and PTEN/p-mTOR (P = 0.009) expression showed shorter survival by univariate but not by multivariate analysis.

CONCLUSIONS

The AKT pathway is activated in a subset of extrahepatic cholangiocarcinoma. Elevated PTEN expression correlates with longer survival. Quantitative data obtained by multiplex tissue immunoblotting may provide additional information than assessment of immunohistochemistry alone. Quantitative analysis of PTEN, PTEN/p-AKT and PTEN/p-mTOR shows differences in survival by univariate analysis.

Tissue microarray: An effective high-throughput method to study the placenta for clinical and research purposes

OBJECTIVE

Tissue microarray (TMA) technology allows simultaneous examination of the expression of many molecular markers (protein, mRNA, DNA, etc.) with high-throughput. The application of this technology, to date, has been largely confined to the study of cancer. Placental pathology poses unique challenges because of the size of the organ, its complex anatomy, as well as its histological heterogeneity. The objective of this study was to assess the feasibility and efficiency of TMAs for immunohistochemistry and in situ hybridization of placental tissues.

STUDY DESIGN

TMAs were constructed using an automated tissue arrayer. Standard 0.6-mm or 1-mm microarray needles were used. Villous parenchyma, basal plate, and chorioamniotic membranes were targeted in each block. Five mum-thick TMA sections underwent immunohistochemical analysis of both cytoplasmic and nuclear antigens using a panel of antibodies against a variety of cytoplasmic [cytokeratin-7, vascular endothelial growth factor (VEGF), and protein Z], membranous (endoglin), and nuclear (c-fos and c-jun) antigens. mRNA in situ hybridization for surfactant protein A (SP-A) and chromogenic in situ hybridization for the Y chromosome (DYZ1) were also performed.

RESULTS

Validation of TMA immunoreactivity demonstrated comparable results with corresponding whole sections. When a two-tiered scoring system (positive/negative) was employed, there was agreement between two and three cores and whole tissue sections (kappa>0.7). When a three-tiered scoring system (negative, weak-positive, or strong-positive) was used, the data from three cores showed the highest agreement with whole tissue sections (kappa >0.7). In situ hybridization experiments for mRNA and DNA were also successful in that the signals were readily detectable. Successful transfer from the donor block to the recipient block differed according to the anatomical compartment. The transfer efficiency of villous parenchyma, basal plate, and chorioamniotic membranes were 96.9% (875/903), 76.7% (115/150), and 75.4% (224/297), respectively.

CONCLUSION

TMA is a practical and effective tool for high-throughput molecular analysis of the human placenta. Duplicate and triplicate cores offer agreement with whole tissue sections for two-category distinction immunostaining. TMA also affords relevant results from in situ hybridization experiments for mRNA and DNA. The major advantages are the conservation of tissues and reagents, simultaneous comparison of molecular markers in different anatomical compartments of the placenta, and reduction of experimental error.

Transfer and multiplex immunoblotting of a paraffin embedded tissue

In the functional proteome era, the proteomic profiling of clinicopathologic annotated tissues is an essential step for mining and evaluations of candidate biomarkers for disease. Previously, application of routine proteomic methodologies to clinical tissue specimens has provided unsatisfactory results. Multiplex tissue immunoblotting is a method of transferring proteins from a formalin-fixed, paraffin-embedded tissue section to a stack of membranes which can be applied to a conventional immunoblotting method. A single tissue section can be transferred to up to ten membranes, each of which is probed with antibodies and detected with fluorescent tags. By this approach, total protein and target signals can be simultaneously determined on each membrane; hence each antibody is internally normalized. Phosphorylation-specific antibodies as well as antibodies that do not readily work well with paraffin-embedded tissue are applicable to the membranes, expanding the menu of antibodies that can be utilized with formalin-fixed tissue. This novel platform can provide quantitative detection retaining histomorphologic detail in clinical samples and has great potential to facilitate discovery and development of new diagnostic assays and therapeutic agents.

A well-based reverse-phase protein array applicable to extracts from formalin-fixed paraffin-embedded tissue

Proteomic analysis of formalin-fixed paraffin-embedded (FFPE) tissue offers significant diagnostic utility but is complicated due to the high level of covalently crosslinked proteins arising from formalin fixation. To address these challenges, we developed a reliable protein extraction method for FFPE tissue, based on heat-induced antigen retrieval within a pressure cooker. The protein extraction yield from archival FFPE tissue section is approximately 90% of that recovered from frozen tissue. This method demonstrates preservation of immunoreactivity and recovery of full-length proteins by Western blotting. Additionally, we developed a well-based RP protein array platform utilizing an electrochemiluminescence detection system. Protein samples derived from FFPE tissue by means of laser capture dissection, with as few as 500 shots demonstrate measurable signal differences for different proteins. The lysates coated to the array plate, remain stable over 1 month at room temperature. Theses data suggest that this new protein-profiling platform coupled with the protein extraction method can be used for molecular profiling analysis in FFPE tissue, and contribute to the validation and development of biomarkers in clinical studies.

Correlation between expression and differentiation of endocan in colorectal cancer

AIM: To investigate the expression frequency of endocan in colorectal cancer and analyze the relationship between endocan expression and clinical parameters and to study the role of endocan in colorectal carcinogenesis.

METHODS: Expression of endocan in 72 tumor tissue samples of colorectal cancer as well as in 27 normal mucous membrane tissue samples was analyzed using in situ hybridization, immunohistochemistry on tissue microarray, Western blot and reverse-transcript polymerase chain reaction (RT-PCR).

RESULTS: The expression of endocan was higher in normal colon and rectum tissue samples than in cancerous tissue samples (mRNA = 92.6%, protein = 36%), and was lower in colorectal cancer tissue samples (mRNA = 70.4%, protein = 36.1%). No correlation was found between staining intensity and clinical parameters such as sex, age, tumor size and TNM stage. However, the expression of endocan was positively correlated with the tissue differentiation in colorectal cancer.

CONCLUSION: The expression of endocan is down-regulated in colorectal cancer and is positively correlated with the tissue differentiation in colorectal cancer, suggesting that the expression of endocan is associated with development and differentiation of colorectal cancer.

Layered peptide array for multiplex immunohistochemistry

Layered peptide array is a new methodology for multiplex molecular measurements from two-dimensional life science platforms. The technology can be used in several different configurations depending on the needs of the investigator. Described here is an indirect layered peptide array (iLPA) that is capable of measuring proteins on a solid surface, such as target antigens on a tissue section. A prototype iLPA system was developed and subsequently examined for reproducibility and specificity and then compared with standard immunohistochemistry. Semiquantitative, multiplex proteomic analysis of histological sections was achieved with up to 20 membranes. The experimental variability was 18%. Overall, the data suggest that iLPA technology will be a relatively simple and inexpensive method for molecular measurements from tissue sections.

Tissue microarrays enabling high-throughput molecular pathology

The tissue microarray has enabled high-throughput pathology. Rather than the laborious review of individual slides and issues of assay reproducibility across large series of specimens, tissue microarrays allow the review of a single stain on a single slide containing tens to hundreds of samples. This is a paradigm shift in pathology, away from histomorphology and toward molecular characterization by immunohistochemistry. This platform allows large retrospective clinical studies of biomarkers for correlation with outcome and can equally well be applied toward high-throughput analysis of cell lines and xenografts. Tissue microarrays encourage novel approaches to assaying tissue with retained histomorphology and have enabled image analysis in pathology. The reduction of tissue to an analyte for high-throughput analysis has highlighted the importance of a high quality tissue and the impact of tissue handling and processing in the quality of data that can be obtained from analysis of tissue.

Expression of EIF3-p48/INT6, TID1 and Patched in cancer, a profiling of multiple tumor types and correlation of expression

Alterations in eIF3-p48/INT6 gene expression have been implicated in murine and human mammary carcinogenesis. We examined levels of INT6 protein in human tumors and determined that breast and colon tumors clustered into distinct groups based on levels of INT6 expression and clinicopathological variables. We performed multiplex tissue immunoblotting of breast, colon, lung, and ovarian tumor tissues and found that INT6 protein levels positively correlated with those of TID1, Patched, p53, c-Jun, and phosphorylated-c-Jun proteins in a tissue-specific manner. INT6 and TID1 showed significant positive correlation in all tissue types tested. These findings were confirmed by immunohistochemical staining of INT6 and TID1. Further evidence supporting a cooperative role for INT6 and TID1 is the presence of endogenous INT6 and TID1 proteins as complexes. We detected co-immunoprecipitation between INT6 and TID1, as well as between INT6 and Patched. These findings suggest potential integrated roles for INT6, TID1, and Patched proteins in cell growth, development, and tumorigenesis. Additionally, these data suggest that the combination of INT6, TID1, and Patched protein levels may be useful biomarkers for the development of diagnostic assays.

Optimization of recovery of RNA from formalin-fixed, paraffin-embedded tissue

Formalin-fixed, paraffin-embedded (FFPE) tissue is the most common specimen available for application of diagnostic assays on tissue after microscopic examination. Not only is there a substantial archive of tissue available, but FFPE tissue remains the best method of preparation for microscopic examination in a routine clinical environment. Molecular assays, especially reverse transcription and polymerase chain reaction and expression array-based assays, offer significant potential as diagnostic, prognostic, and predictive tools, but require high quality RNA. Herein, we have optimized a reliable RNA extraction method for FFPE tissue. It is based on deparaffinization at high temperature coupled with a 3-day lysis at 65 degrees C. The average total RNA yield is 4.5 to 5.5 pg per 1 microm of archival FFPE tissue, and 260/280 ratios are between 1.80 and 1.95. The extracted RNA has a modal fragment length between 100 and 200 nt by the Bioanalyzer analysis. Although modal lengths of RNA fragments were shorter, reverse transcription and polymerase chain reaction was able to amplify amplicons in range of 300 bp. Pretreatment with RNA, later followed by formalin fixation, did not result in improving the RNA quality, but did improve RNA yield. Our method improves the utility of FFPE tissue for molecular profiling studies.

Tissue microarrays as a platform for proteomic investigation

Tissue microarrays have become an essential tool in translational pathology. They are used to confirm results from other experimental platforms, such as expression microarrays, as well as a primary tool to explore the expression profile of proteins by immunohistochemical analysis. Tissue microarrays are routinely used molecular epidemiology, drug development and determining the diagnostic, prognostic and predictive value of new biomarkers. By applying traditional protein based assays, as well as novel assays to the platform, tissue microarrays have gained a new utility as a proteomic tool for both basic science as well as clinical investigation. This article will explore the new approaches that are being applied to tissue microarrays to, characterize the human proteome, and new technologies that allow tissue microarrays to function as a protein array.

Layered expression scanning: multiplex molecular analysis of diverse life science platforms

With the advent of the genomic era, there is an increasing use of high-throughput techniques to generate transcriptome- and proteome-based profiles of biological specimens. Each of these methodologies offers a unique window into the inner workings of cell and tissue samples. Often, these studies generate large data sets and provide investigators with a substantial number of candidate dysregulated genes and pathways. Follow-up studies are then undertaken to independently validate the original findings and to extend the study to additional samples or more quantitative measurements. Although there are several methods available for these validation efforts, they are often tedious and laborious to perform; thus, additional tools that enable this task are needed. One such approach is layered expression scanning (LES), a new technique developed via a cooperative research and development agreement (CRADA) between the National Cancer Institute and 20/20 GeneSystems, Inc. The technique is based on the movement of biomolecules from a two-dimensional life science platform (histological tissue section, electrophoresis gel, multi-well plate, etc.) through a set of analysis membranes while maintaining the original distribution pattern of the molecules. Each membrane measures one analyte and the data are then mapped back to the original specimen, permitting each component of the life science platform to be studied in detail. LES can be configured in several different ways depending on the goals of the study. In this review, we summarize the use of the LES technique for a variety of biological applications.

A Multiplex Tissue Immunoblotting Assay for Proteomic Profiling: A Pilot Study of the Normal to Tumor Transition of Esophageal Squamous Cell Carcinoma

Esophageal cancer remains a highly lethal malignancy for which the genetic and proteomic events are poorly understood. Studies have reported dysregulated proteins in esophageal carcinoma; however, the magnitude of these changes remains largely uncharacterized. Little is known about alterations early in the neoplastic pathway. Using multiplex tissue immunoblotting, we quantified the expression of seven proteins in esophageal carcinogenesis. Regions of normal, dysplasia, and invasive carcinoma of the squamous esophagus in six patients were characterized. Pan-cytokeratin (CK) was essentially unchanged across the transition (0.96 in dysplasia and 0.69 in tumor). Expression levels of annexin 1, CK-4, and CK-14 were all decreased in dysplasia and tumor compared with normal (reference, 1.00): annexin 1, 0.30 in dysplasia and 0.15 in tumor; CK-4, 0.20 in dysplasia and 0.16 in tumor; and CK-14, 0.54 in dysplasia and 0.40 in tumor. Expression of two proteins was increased in dysplasia and tumor versus normal: cyclooxygenase-2, 1.35 in dysplasia and 2.32 in tumor and p53, 1.29 in dysplasia and 2.37 in tumor. Secreted protein, acidic and rich in cysteine, which is expressed in the adjacent stroma, was 1.56-fold higher in stroma underlying dysplasia and 6.20-fold increased in dysplastic stroma surrounding invasive tumor. These findings suggest that changes in protein expression can be detected during the transition to dysplasia and may be useful biomarkers.