Kelli Montgomery

Gene Expression Signature of Fibroblast Serum Response Predicts Human Cancer Progression: Similarities between Tumors and Wounds

Cancer invasion and metastasis have been likened to wound healing gone awry. Despite parallels in cellular behavior between cancer progression and wound healing, the molecular relationships between these two processes and their prognostic implications are unclear. In this study, based on gene expression profiles of fibroblasts from ten anatomic sites, we identify a stereotyped gene expression program in response to serum exposure that appears to reflect the multifaceted role of fibroblasts in wound healing. The genes comprising this fibroblast common serum response are coordinately regulated in many human tumors, allowing us to identify tumors with gene expression signatures suggestive of active wounds. Genes induced in the fibroblast serum-response program are expressed in tumors by the tumor cells themselves, by tumor-associated fibroblasts, or both. The molecular features that define this wound-like phenotype are evident at an early clinical stage, persist during treatment, and predict increased risk of metastasis and death in breast, lung, and gastric carcinomas. Thus, the transcriptional signature of the response of fibroblasts to serum provides a possible link between cancer progression and wound healing, as well as a powerful predictor of the clinical course in several common carcinomas.

The Novel Marker, DOG1, Is Expressed Ubiquitously in Gastrointestinal Stromal Tumors Irrespective of KIT or PDGFRA Mutation Status

We recently characterized gene expression patterns in gastrointestinal stromal tumors (GISTs) using cDNA microarrays, and found that the gene FLJ10261 (DOG1, discovered on GIST-1), encoding a hypothetical protein, was specifically expressed in GISTs. The immunoreactivity of a rabbit antiserum to synthetic DOG1 peptides was assessed on two soft tissue tumor microarrays. The tissue microarrays included 587 soft tissue tumors, with 149 GISTs, including 127 GIST cases for which the KIT and PDGFRA mutation status was known. Immunoreactivity for DOG1 was found in 136 of 139 (97.8%) of scorable GISTs. All seven GIST cases with a PDGFRA mutation were DOG1-positive, while most of these failed to react for KIT. The immunohistochemical findings were confirmed with in situ hybridization probes for DOG1, KIT, and PDGFRA. Other neoplasms in the differential diagnosis of GIST, including desmoid fibromatosis (0 of 17) and Schwannoma (0 of 3), were immunonegative for DOG1. Only 4 of 438 non-GIST cases were immunoreactive for DOG1. DOG1, a protein of unknown function, is expressed strongly on the cell surface of GISTs and is rarely expressed in other soft tissue tumors. Reactivity for DOG1 may aid in the diagnosis of GISTs, including PDGFRA mutants that fail to express KIT antigen, and lead to appropriate treatment with imatinib mesylate, an inhibitor of the KIT tyrosine kinase.

A Novel Monoclonal Antibody Against DOG1 is a Sensitive and Specific Marker for Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GIST) occur primarily in the wall of the intestine and are characterized by activating mutations in the receptor tyrosine kinases genes KIT or PDGFRA. The diagnosis of GIST relies heavily on the demonstration of KIT/CD117 protein expression by immunohistochemistry. However, KIT expression is absent in ∼4% to 15% of GIST and this can complicate the diagnosis of GIST in patients who may benefit from treatment with receptor tyrosine kinase inhibitors. We previously identified DOG1/TMEM16A as a novel marker for GIST using a conventional rabbit antipeptide antiserum and an in situ hybridization probe. Here, we describe 2 new monoclonal antibodies against DOG1 (DOG1.1 and DOG1.3) and compare their staining profiles with KIT and CD34 antibodies on 447 cases of GIST. These included 306 cases with known mutational status for KIT and PDGFRA from a molecular consultation service. In addition, 935 other mesenchymal tumors and 432 nonsarcomatous tumors were studied. Both DOG1 antibodies showed high sensitivity and specificity for GIST, with DOG1.1 showing some advantages. This antibody yielded positive staining in 370 of 425 (87%) scorable GIST, whereas CD117 was positive in 317 of 428 (74%) GIST and CD34 in 254 of 430 (59%) GIST. In GIST with mutations in PDGFRA, 79% (23/29) showed DOG1.1 immunoreactivity while only 9% (3/32) and 27% (9/33) stained for CD117 and CD34, respectively. Only 1 of 326 (0.3%) leiomyosarcomas and 1 of 39 (2.5%) synovial sarcomas among the 935 soft tissue tumors examined showed positive immunostaining for DOG1.1. In addition, DOG1.1 immunoreactivity was seen in fewer cases of carcinoma, melanoma, and seminoma as compared with KIT.

Bone morphogenetic protein antagonist gremlin 1 is widely expressed by cancer-associated stromal cells and can promote tumor cell proliferation

Although tissue microenvironments play critical roles in epithelial development and tumorigenesis, the factors mediating these effects are poorly understood. In this work, we used a genomic approach to identify factors produced by cells in the microenvironment of basal cell carcinoma (BCC) of the skin, one of the most common human cancers. The global gene expression programs of stromal cell cultures derived from human BCCs showed consistent, systematic differences from those derived from nontumor skin. The gene most consistently expressed at a higher level in BCC tumor stromal cells compared with those from nontumor skin was GREMLIN 1, which encodes a secreted antagonist of the bone morphogenetic protein (BMP) pathway. BMPs and their antagonists are known to play a crucial role in stem and progenitor cell biology as regulators of the balance between expansion and differentiation. Consistent with the hypothesis that BMP antagonists might have a similar role in cancer, we found GREMLIN 1 expression in the stroma of human BCC tumors but not in normal skin in vivo. Furthermore, BMP 2 and 4 are expressed by BCC cells. Ex vivo, BMP inhibits, and Gremlin 1 promotes, proliferation of cultured BCC cells. We further found that GREMLIN 1 is expressed by stromal cells in many carcinomas but not in the corresponding normal tissue counterparts that we examined. Our data suggest that BMP antagonists may be important constituents of tumor stroma, providing a favorable microenvironment for cancer cell survival and expansion in many cancers.

A DNA microarray survey of gene expression in normal human tissues

BackgroundNumerous studies have used DNA microarrays to survey gene expression in cancer and other disease states. Comparatively little is known about the genes expressed across the gamut of normal human tissues. Systematic studies of global gene-expression patterns, by linking variation in the expression of specific genes to phenotypic variation in the cells or tissues in which they are expressed, provide clues to the molecular organization of diverse cells and to the potential roles of the genes.ResultsHere we describe a systematic survey of gene expression in 115 human tissue samples representing 35 different tissue types, using cDNA microarrays representing approximately 26,000 different human genes. Unsupervised hierarchical cluster analysis of the gene-expression patterns in these tissues identified clusters of genes with related biological functions and grouped the tissue specimens in a pattern that reflected their anatomic locations, cellular compositions or physiologic functions. In unsupervised and supervised analyses, tissue-specific patterns of gene expression were readily discernable. By comparative hybridization to normal genomic DNA, we were also able to estimate transcript abundances for expressed genes.ConclusionsOur dataset provides a baseline for comparison to diseased tissues, and will aid in the identification of tissue-specific functions. In addition, our analysis identifies potential molecular markers for detection of injury to specific organs and tissues, and provides a foundation for selection of potential targets for selective anticancer therapy.

Software tools for high-throughput analysis and archiving of immunohistochemistry staining data obtained with tissue microarrays.

The creation of tissue microarrays (TMAs) allows for the rapid immunohistochemical analysis of thousands of tissue samples, with numerous different antibodies per sample. This technical development has created a need for tools to aid in the analysis and archival storage of the large amounts of data generated. We have developed a comprehensive system for high-throughput analysis and storage of TMA immunostaining data, using a combination of commercially available systems and novel software applications developed in our laboratory specifically for this purpose. Staining results are recorded directly into an Excel worksheet and are reformatted by a novel program (TMA-Deconvoluter) into a format suitable for hierarchical clustering analysis or other statistical analysis. Hierarchical clustering analysis is a powerful means of assessing relatedness within groups of tumors, based on their immunostaining with a panel of antibodies. Other analyses, such as generation of survival curves, construction of Cox regression models, or assessment of intra- or interobserver variation, can also be done readily on the reformatted data. Finally, the immunoprofile of a specific case can be rapidly retrieved from the archives and reviewed through the use of Stainfinder, a novel web-based program that creates a direct link between the clustered data and a digital image database. An on-line demonstration of this system is available at http://genome-www.stanford.edu/TMA/explore.shtml.

Analysis of MUM1/IRF4 Protein Expression Using Tissue Microarrays and Immunohistochemistry

The gene encoding MUM1 was characterized as a possible translocation partner in chromosomal abnormalities involving a significant number of multiple myelomas. The overexpression of the MUM1 protein as a result of translocation t(6;14) (p25;q32) identified MUM1 as a putative regulatory molecule involved in B-cell differentiation and tumorigenesis. The expression of MUM1 protein in multiple myelomas supports this hypothesis. In the current study, using tissue microarray technology, we have tested the expression of the MUM1 protein in 1335 human malignancies and normal tissues. Our data show that the MUM1 protein is expressed in a wide spectrum of hematolymphoid neoplasms and in malignant melanomas but is absent in other human tumors. In addition, in tissue microarrays as well as in conventional paraffin sections, MUM1 staining was found to lack specificity in detecting plasmacytic differentiation as compared with two markers, CD138/Syndecan and VS38, commonly used in paraffin immunohistochemistry for detection of plasma cells.

Hep Par 1 antibody stain for the differential diagnosis of hepatocellular carcinoma: 676 tumors tested using tissue microarráys and conventional tissue sections

A well-characterized positive marker for hepatocellular differentiation would be a useful tool for the diagnosis of hepatocellular carcinoma (HCC). The recently commercially available Hep Par 1 antibody (clone OCH1E5.2.10) has been reported to be a sensitive marker for HCC in paraffin embedded sections. Of non-hepatocellular tumors, occasional carcinomas have been reported to stain, most frequently gastric adenocarcinomas. This study further evaluated the staining of this antibody on a large number of neoplasms using tissue microarray technology as well as conventional tissue sections. Six hundred seventy-six tumors, including 19 cases of HCC, were tested. Eighteen of 19 cases of HCC were positive, 3 showing <5% staining. Two cases negative on the array showed focal staining when whole tissue sections from the same tumors were used. 16 of 34 cases of gastric carcinomas gave positive reactions, 4 of these showed less than 5% staining. Staining of gastric carcinomas was not limited to signet ring-type carcinomas or to areas of hepatoid differentiation. Only 1 of 11 cases of cholangiocarcinoma showed focal staining. We also noted several other tumors to stain occasionally, including adrenal cortical carcinoma (3/13), yolk sac tumor (2/9), colonic adenocarcinoma (8/106), lung carcinoma (3/52), ovarian carcinoma (5/48), and endocervical adenocarcinoma (1/5). We did not observe staining in pancreatic carcinoma (11), renal cell carcinoma (36), breast carcinoma (85), melanoma (25), or mesothelioma (5). This study supports Hep Par 1 as a useful marker in the differential diagnosis of HCC, but with significant limitations. Cautious use of this antibody in a panel with other positive (alpha fetoprotein, CD10, polyclonal carcinoembryonic antigen) and negative (epithelial membrane antigen, monoclonal carcinoembryonic antigen, CD15) markers of hepatocellular differentiation may aid in the accurate diagnosis of HCC.

MYB Expression and Translocation in Adenoid Cystic Carcinomas and Other Salivary Gland Tumors With Clinicopathologic Correlation

Background Adenoid cystic carcinoma is a locally aggressive salivary gland neoplasm, which has a poor long-term prognosis. A chromosomal translocation involving the genes encoding the transcription factors, MYB and NFIB, has been recently discovered in these tumors. Methods MYB translocation and protein expression were studied in 37 adenoid cystic carcinomas, 112 other salivary gland neoplasms, and 409 nonsalivary gland neoplasms by fluorescence in situ hybridization and immunohistochemistry. MYB translocation and expression status in adenoid cystic carcinoma was correlated with clinicopathologic features including outcome, with a median follow-up of 77.1 months (range, 23.2 to 217.5 mo) for living patients. Results A balanced translocation between MYB and NFIB is present in 49% of adenoid cystic carcinomas but is not identified in other salivary gland tumors or nonsalivary gland neoplasms. There is no apparent translocation of MYB in 35% of the cases. Strong Myb immunostaining is very specific for adenoid cystic carcinomas but is only present in 65% of all cases. It is interesting to note that Myb immunostaining is confined to the basal cell component although the translocation is present in all the cells. Neoplasms with MYB translocation show a trend toward higher local relapse rates, but the results are not statistically significant with the current number of cases. Conclusions MYB translocation and expression are useful diagnostic markers for a subset of adenoid cystic carcinomas. The presence of the translocation may be indicative of local aggressive behavior, but a larger cohort may be required to show statistical significance.

Placental S100 (S100p) and GATA3 : Markers for transitional epithelium and urothelial carcinoma discovered by complementary DNA microarray

The morphologic distinction between prostate and urothelial carcinoma can be difficult. To identify novel diagnostic markers that may aid in the differential diagnosis of prostate versus urothelial carcinoma, we analyzed expression patterns in prostate and bladder cancer tissues using complementary DNA microarrays. Together with our prior studies on renal neoplasms and normal kidney, these studies suggested that the gene for placental S100 (S100P) is specifically expressed in benign and malignant urothelial cells. Using tissue microarrays, a polyclonal antiserum against S100P protein stained 86% of 295 urothelial carcinomas while only 3% of 260 prostatic adenocarcinomas and 1% of 133 renal cell carcinomas stained. A commercially available monoclonal antibody against S100P stained 78% of 300 urothelial carcinomas while only 2% of 256 prostatic adenocarcinomas and none of 137 renal cell carcinomas stained. A second gene, GATA3, also showed high level expression in urothelial tumors by cDNA array. A commercially available monoclonal antibody against GATA3 stained 67% of 308 urothelial carcinomas, but none of the prostate or renal carcinomas. For comparison, staining was also performed for p63 and cytokeratin 5/6. p63 stained 87% of urothelial carcinomas whereas CK5/6 stained 54%. Importantly, when S100P and p63 were combined 95% of urothelial carcinomas were labeled by one or both markers. We conclude that the detection of S100P and GATA3 protein expression may help distinguish urothelial carcinomas from other genitourinary neoplasms that enter into the differential diagnosis.