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1.  Decrease in CD8+ lymphocyte number and altered cytokine profile in human prostate cancer 
The tumor microenvironment is comprised of multiple cell types arranged in a three-dimensional structure. Interactions amongst the various cell components play an important role in neoplasia, including the inflammatory reaction that occurs as part of the host response. In this study, the regional lymphocyte subpopulations and cytokine profiles associated with prostate cancer were examined using a quantitative imaging approach and expression microarray analysis. Lymphocytes were measured in four different epithelial phenotypes in prostate cancer specimens: carcinoma; prostatic intraepithelial neoplasia (PIN); benign prostate hyperplasia (BPH); and normal epithelium. The data indicate that CD8 positive, cytotoxic T lymphocytes are significantly decreased in regions adjacent to hyperplasia and carcinoma as compared to normal epithelium and PIN. In contrast the relative number of CD4 positive and CD20 positive lymphocytes did not change markedly. Parallel mRNA expression array analysis of the normal and tumor microenvironments identified a distinct cytokine profile in cancer, with 24 dysregulated genes in tumor epithelium and nine altered in tumor-associated stroma. Overall, these data indicate that the spatial distribution of CD8 positive, cytotoxic T lymphocytes is dysregulated in human prostate glands that contain cancer, and cytokine profiles are altered at the mRNA level.
PMCID: PMC3180108  PMID: 21969236
Prostate cancer; lymphocytes; cytokines; histomathematics; histopathology
2.  Increased matrix metalloproteinase activation in esophageal squamous cell carcinoma 
Esophageal squamous cell carcinomas (ESCC) are usually asymptomatic and go undetected until they are incurable. Cytological screening is one strategy to detect ESCC at an early stage and has shown promise in previous studies, although improvement in sensitivity and specificity are needed. Proteases modulate cancer progression by facilitating tumor invasion and metastasis. In the current study, matrix metalloproteinases (MMPs) were studied in a search for new early detection markers for ESCC.
Protein expression levels of MMPs were measured using zymography in 24 cases of paired normal esophagus and ESCC, and in the tumor-associated stroma and tumor epithelium in one sample after laser capture microdissection (LCM). MMP-3 and MMP-10 transcripts in both the epithelium and stroma in five cases were further analyzed by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR).
Gelatin zymography showed bands corresponding in size to MMP-2, MMP-3, MMP-9, and MMP-10 enzymes in each of the 24 cancer cases. MMP levels tended to be higher in tumors than paired normal tissue; however, only the 45 kDa band that corresponds to the activated form of MMP-3 and MMP-10 was strongly expressed in all 24 tumors with little or no expression in the paired normal foci. LCM-based analysis showed the 45 kDA band to be present in both the stromal and epithelial components of the tumor microenvironment, and that MMP-3 and MMP-10 mRNA levels were higher in tumors than paired normal tissues for each compartment.
Increased levels of MMPs occur in ESCC suggesting their up-regulation is important in esophageal tumorigenesis. The up-regulated gene products have the potential to serve as early detection markers in the clinic.
PMCID: PMC2958908  PMID: 20920372
3.  Influence of hypoxia induced by minimally invasive prostatectomy on gene expression: implications for biomarker analysis 
Handling and processing of clinical specimens during and after surgical resection may significantly skew the molecular data obtained from analysis of those samples. Minimally invasive prostatectomy was used as a model to specifically study effects of surgical ischemia on gene expression in human clinical samples. Normal prostatic urethra cup biopsies were procured from 12 patients at three time points during laparoscopic radical prostatectomy. Homogeneous cells (stroma and epithelium) were microdissected. Transcript analysis of 3 oxygen-dependent, 3 oxygen-independent, and 3 control class genes was performed using quantitative RT-PCR. Data were analyzed by relative quantitation and two-sided t-test. Patient demographic and time covariates were fit by a linear mixed model. VEGF, an oxygen-dependent gene, showed significant expression alterations across three time points in epithelium (p=0.008), but not in stroma (p=0.66). Expression levels of VHL, STAT5B, and CYPA showed significant changes at the p<0.05 level in the stroma only. Effects of age, PSA, prostate size, Gleason score, surgery type, total surgery time, total ischemia time, and estimated blood loss on VEGF expression over time were not significant at the p<0.01 level. Therefore, surgical manipulation and tissue processing methods need to be taken into account when assessing prostatic biomarkers; however, resection does not dramatically alter mRNA profiles in prostate specimens.
PMCID: PMC2892411  PMID: 20589162
Laparoscopic surgery; prostatectomy; warm ischemia; hypoxia; tissue microdissection; gene expression analysis
4.  Quantitative RT-PCR gene expression analysis of laser microdissected tissue samples 
Nature protocols  2009;4(6):902-922.
Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is a valuable tool for measuring gene expression in biological samples. However, unique challenges are encountered when studies are performed on cells microdissected from tissues derived from animal models or the clinic, including specimen related issues, variability of RNA template quality and quantity, and normalization. qRT-PCR using small amounts of mRNA derived from dissected cell populations requires adaptation of standard methods to allow meaningful comparisons across sample sets. The protocol described here presents the rationale, technical steps, normalization strategy, and data analysis necessary to generate reliable gene expression measurements of transcripts from dissected samples. The entire protocol from tissue microdissection through qRT-PCR analysis requires approximately 16 hours.
PMCID: PMC2760821  PMID: 19478806
quantitative measurements; microdissected tissues; qRT-PCR; validation; gene expression analysis; protocol; normalization strategy
5.  Molecular Alterations in Primary Prostate Cancer After Androgen Ablation Therapy 
After an initial response to androgen ablation, most prostate tumors recur, ultimately progressing to highly aggressive androgen independent (AI) cancer. The molecular mechanisms underlying progression are not well known, in part due to the rarity of AI samples from primary and metastatic sites.
We compared the gene expression profiles of ten AI primary prostate tumor biopsies with ten primary, untreated androgen-dependent (AD) tumors. Samples were laser capture microdissected, the RNA was amplified, and gene expression was assessed using Affymetrix Human Genome U133A Gene Chips. Differential expression was examined with principle component analysis (PCA) and Student t testing. Analysis of gene ontology was performed with Expression Analysis Systematic Explorer (EASE) and gene expression data were integrated with genomic alterations with DIfferential Gene locus MAPping (DIGMAP).
Unsupervised PCA showed that the AD and AI tumors segregated from one another. After filtering the data, 239 differentially expressed genes were identified. Two main gene ontologies were found discordant between AI and AD tumors: macromolecule biosynthesis was down-regulated and cell adhesion up-regulated in AI tumors. Other differentially expressed genes were related to IL-6 signaling, as well as angiogenesis, cell adhesion, apoptosis, oxidative stress, and hormone response. The DIGMAP analysis identified nine regions of potential chromosomal deletion in the AI tumors including 1p36, 3p21, 6p21, 8p21, 11p15, 11q12, 12q23, 16q12, and 16q21.
Taken together, these data identify several unique characteristics of AI prostate cancer that may hold potential for the development of targeted therapeutic intervention.
PMCID: PMC1432092  PMID: 16203770
microarrays; androgen-independent prostate cancer; laser capture microdissection; RNA amplification
6.  Tumor-associated endothelial cells display GSTP1 and RARβ2 promoter methylation in human prostate cancer 
A functional blood supply is essential for tumor growth and proliferation. However, the mechanism of blood vessel recruitment to the tumor is still poorly understood. Ideally, a thorough molecular assessment of blood vessel cells would be critical in our comprehension of this process. Yet, to date, there is little known about the molecular makeup of the endothelial cells of tumor-associated blood vessels, due in part to the difficulty of isolating a pure population of endothelial cells from the heterogeneous tissue environment.
Here we describe the use of a recently developed technique, Expression Microdissection, to isolate endothelial cells from the tumor microenvironment. The methylation status of the dissected samples was evaluated for GSTP1 and RARβ2 promoters via the QMS-PCR method.
Comparing GSTP1 and RARβ2 promoter methylation data, we show that 100% and 88% methylation is detected, respectively, in the tumor areas, both in epithelium and endothelium. Little to no methylation is observed in non-tumor tissue areas.
We applied an accurate microdissection technique to isolate endothelial cells from tissues, enabling DNA analysis such as promoter methylation status. The observations suggest that epigenetic alterations may play a role in determining the phenotype of tumor-associated vasculature.
PMCID: PMC1420331  PMID: 16512911

Results 1-6 (6)