The significance of Trk receptors in pancreatic cancer.

This study investigated the Trk receptor family as a therapeutic target in pancreatic ductal adenocarcinoma and assessed their prognostic significance. Global gene expression analysis was investigated in prospectively collected pancreatic ductal adenocarcinomas that had either undergone neoadjuvant chemoradiation or were treated by surgery. PANC-1 and MIA-PaCa-2 cell lines were investigated to establish whether fractionated radiation altered expression of four neuroendocrine genes and whether this resulted in subsequent changes in radiosensitivity. A specific inhibitor of TrkA, B, and C, AstraZeneca 1332, was investigated in vitro and in vivo in combination with radiation. A tissue microarray was constructed from 77 pancreatic ductal adenocarcinoma patients who had undergone neoadjuvant chemoradiation and the Trk receptor, and neurogenic differentiation 1 expression was assessed and correlated with overall survival. A total of 99 genes were identified that were differentially expressed in the chemoradiation patients with neuroendocrine genes and pathways, in particular the neurogenic differentiation 1 and Trk receptor family, being prominent. Fractionated radiation upregulated the expression of neuroendocrine genes, and AstraZeneca 1332 treatment in vitro enhanced radiosensitivity. No added effect of AstraZeneca 1332 was observed in vivo. Trk receptor expression varied between isoforms but did not correlate significantly with clinical outcome. Radiation treatment upregulated neuroendocrine gene expression but the Trk receptor family does not appear to be a promising treatment target.

Analytical validation of a novel panel of biomarkers for a test for preeclampsia.

Preeclampsia is a serious condition responsible for much pregnancy-related morbidity and mortality. Diagnosis of preeclampsia is difficult due to the non-specific and subjective nature of symptoms of the disease. To reduce the subjective decision making and management of preeclampsia, we identified a panel of biomarkers representing multiple and different pathogenic pathways implicated in the etiology of preeclampsia, and developed a test referred to as Preecludia™. An algorithm based on eight biomarkers (cluster of differentiation 274 (CD274), decorin, endoglin, fibroblast growth factor-21 (FGF21), soluble fms-related tyrosine kinase 1 (sFlt-1), kidney injury molecule-1 (KIM-1), free placental growth factor (PlGF), and total PlGF) and gestational age at the time of sample collection was constructed to rule out preeclampsia in women presenting with signs and symptoms of preeclampsia. The analytical performance of each of the individual biomarker assays that comprise the Preecludia™ test was evaluated. Herein we report the test's precision, analytical range, analytical sensitivity, parallelism, linearity, interference, analytical specificity, analytical accuracy, and stability. The data indicate that these biomarker assays exhibit a high level of inter-run precision of less than 15%, with minimal interference.

Using global gene expression to discriminate thin melanomas with poor outcomes.

Most melanomas present as thin lesions (≤1.0 mm) with a good prognosis; however, a small percentage of patients with thin lesions experience recurrence or metastasis. The aim of our study was to identify a distinct pattern of gene expression within thin melanomas known to have eventually metastasized to regional lymph nodes or distant sites compared with those that followed the typical course with good response to wide local excision alone. Patients who were disease-free for a minimum of 10 y served as controls (n = 10) to the experimental group who developed metastasis (n = 9). Laser capture microdissection was used to specifically isolate cancer cells from formalin-fixed paraffin-embedded tissue with subsequent gene expression analysis on Affymetrix Human Transcriptome Array 2.0 Arrays. Although gene expression differences were observed between the patients with thin melanoma with poor clinical outcome and those with good clinical outcome, neither the number of genes nor the magnitude of the fold difference was very substantial or significant. Cluster analysis with this subset of genes could definitively separate a subset of the poor responders from the good responders, but there remained a mixed group of tumors that could not be predicted from gene expression alone. Pathway analysis identified cellular processes that were regulated based on the response, including categories commonly associated with melanoma progression. Ultimately, we concluded that there were very few differences between these groups. Future research will be required and investigation of the mutational landscape may be another strategy to uncover genomic changes that drive recurrence and metastasis in thin melanoma.

Utilizing In-House Resources to Correct Sample Mixups in a Medium Throughput Biorepository: A Case Study.

Given the high demands on a multidisciplinary approach to sample collection, and despite the rigorous quality assurance and quality control measures designed to minimize sample misidentification in our state of the art biorepository, the potential for error is still a concern. Measures to deal with potential uncertainties are a necessary part of every successful biobanking operation. The Beaumont BioBank and associated Core Molecular Laboratory have developed procedures to address these rare incidents. Here we present a case study of occurrences in the Beaumont BioBank in which the identity of samples was uncertain and a resolution workflow was implemented to quickly remove the ambiguity. Using Core Molecular Laboratory in-house resources, including Mass Array technology and the valuable insight and experience from a multidisciplinary team, a comprehensive troubleshooting schema has been developed and applied toward resolving sample identification uncertainties. As per standard operating procedures, each step of these incidents was recorded and a final report prepared.

Characterization of clear cell renal cell carcinoma by gene expression profiling.

OBJECTIVES: Use global gene expression to characterize differences between high-grade and low-grade clear cell renal cell carcinoma (ccRCC) compared with normal and benign renal tissue. METHODS: Tissue samples were collected from patients undergoing surgical resection for ccRCC. Affymetrix gene expression arrays were used to examine global gene expression patterns in high- (n = 16) and low-grade ccRCC (n = 13) as well as in samples from normal kidney (n =14) and benign kidney disease (n = 6). Differential gene expression was determined by analysis of variance with a false discovery rate of 1% and a 2-fold cutoff. RESULTS: Comparing high-grade ccRCC with each of normal and benign kidney resulted in 1,833 and 2,208 differentially expressed genes, respectively. Of these, 930 were differentially expressed in both comparisons. In order to identify genes most related to progression of ccRCC, these differentially expressed genes were filtered to identify genes that showed a pattern of expression with a magnitude of change greater in high-grade ccRCC in the comparison to low-grade ccRCC. This resulted in the identification of genes such as TMEM45A, ceruloplasmin, and E-cadherin that were involved in cell processes of cell differentiation and response to hypoxia. Additionally changes in HIF1α and TNF signaling are highly represented by changes between high- and low-grade ccRCC. CONCLUSIONS: Gene expression differences between high-grade and low-grade ccRCC may prove to be valuable biomarkers for advanced ccRCC. In addition, altered signaling between grades of ccRCC may provide important insight into the biology driving the progression of ccRCC and potential targets for therapy.

Cancer Stem Cell Signaling during Repopulation in Head and Neck Cancer.

The aim of the study was to investigate cancer stem signaling during the repopulation response of a head and neck squamous cell cancer (HNSCC) xenograft after radiation treatment. Xenografts were generated from low passage HNSCC cells and were treated with either sham radiation or 15 Gy in one fraction. At different time points, days 0, 3, and 10 for controls and days 4, 7, 12, and 21, after irradiation, 3 tumors per group were harvested for global gene expression, pathway analysis, and immunohistochemical evaluation. 316 genes were identified that were associated with a series of stem cell-related genes and were differentially expressed (p ≤ 0.01 and 1.5-fold) at a minimum of one time point in UT-SCC-14 xenografts after radiation. The largest network of genes that showed significant changes after irradiation was associated with CD44, NOTCH1, and MET. c-MET and ALDH1A3 staining correlated with the changes in gene expression. A clear pattern emerged that was consistent with the growth inhibition data in that genes associated with stem cell pathways were most active at day 7 and day 12 after irradiation. The MET/CD44 axis seemed to be an important component of the repopulation response.

Gene Expression Characterization of HPV Positive Head and Neck Cancer to Predict Response to Chemoradiation.

Human papillomavirus (HPV) has been shown to have a causal role in the development of head and neck squamous cell carcinoma. While HPV-positive head and neck cancer is associated with a better response to treatment in the majority of patients, there is a subset who does not respond favorably to current therapy. Identification of these patients could prevent unnecessary morbidity and indicate the need for alternative therapeutic options. Tissue samples were obtained from 19 patients with HPV-positive head and neck squamous carcinoma treated with chemoradiation therapy. HPV status was confirmed by polymerase chain reaction analysis through detection of HPV16 E7 in both DNA and RNA. RNA was isolated from tissue samples and subjected to microarray gene expression analysis. In addition to identification of potential genetic biomarkers (including LCE3D, KRTDAP, HMOX1, KRT19, MDK, TSPAN1), differentially expressed genes associated with genomic stability, cell cycle, and DNA damage were detected between responders and non-responders. These results were further validated with publicly available gene expression studies. This pilot study suggests prospective biomarkers that predict response to therapy. The importance of genes involved with genomic stability is highlighted in both development and progression of head and neck squamous cell carcinoma but also recurrence. Potential development of an assay may prove beneficial to clinicians, assisting them to provide alternative care sooner thus lowering morbidity.

Gene expression differences predict treatment outcome of merkel cell carcinoma patients.

Due to the rarity of Merkel cell carcinoma (MCC), prospective clinical trials have not been practical. This study aimed to identify biomarkers with prognostic significance. While sixty-two patients were identified who were treated for MCC at our institution, only seventeen patients had adequate formalin-fixed paraffin-embedded archival tissue and followup to be included in the study. Patients were stratified into good, moderate, or poor prognosis. Laser capture microdissection was used to isolate tumor cells for subsequent RNA isolation and gene expression analysis with Affymetrix GeneChip Human Exon 1.0 ST arrays. Among the 191 genes demonstrating significant differential expression between prognostic groups, keratin 20 and neurofilament protein have previously been identified in studies of MCC and were significantly upregulated in tumors from patients with a poor prognosis. Immunohistochemistry further established that keratin 20 was overexpressed in the poor prognosis tumors. In addition, novel genes of interest such as phospholipase A2 group X, kinesin family member 3A, tumor protein D52, mucin 1, and KIT were upregulated in specimens from patients with poor prognosis. Our pilot study identified several gene expression differences which could be used in the future as prognostic biomarkers in MCC patients.

Gene expression changes during repopulation in a head and neck cancer xenograft.

BACKGROUND/PURPOSE: To investigate temporal changes in global gene expression and pathways involved in the response to irradiation during phases of growth inhibition, recovery and repopulation in a human head and neck squamous cell cancer (HNSCC) xenograft. METHODS AND MATERIALS: Low passage head and neck squamous cancer cells (UT-14-SCC) were injected into the flanks of female nu/nu mice to generate xenografts. After tumors reached a size of 500 mm3, they were treated with either sham RT or 15Gy in one fraction. At different time points, days 0, 3, and 10 for controls and days 4, 7, 12, and 21 after irradiation, the tumors were harvested for global gene expression analysis and pathway analysis. RESULTS: The tumors showed growth inhibition through days 4-7 and began the transition to regrowth around the day 12 time point. When comparing the pooled controls to each day of treatment, there were 22, 119, 125, and 25 differentially expressed genes on days 4, 7, 12, and 21 respectively using a p⩽0.01 and a 2-fold cut-off. Gene Ontology (GO), gene set enrichment analysis (GSEA) and sub-network enrichment analysis (SNEA) identified different biological processes, cell process pathways and expression targets to be active on each time point after irradiation. An important observation was that the molecular events on day 12 which represented the transition from growth inhibition to regrowth identified interferon and cytokine related genes and signaling pathways as the most prominent. CONCLUSION: The findings in this study compliment research which has identified components of interferon-related signaling pathways to be involved in radioresistance. Further work will be required to understand the significance of these genes in both radioresistance and treatment response leading to new therapeutic strategies and prognostic tools.

Glucose metabolism gene expression patterns and tumor uptake of ¹8F-fluorodeoxyglucose after radiation treatment.

PURPOSE: To investigate whether radiation treatment influences the expression of glucose metabolism genes and compromises the potential use of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) as a tool to monitor the early response of head and neck cancer xenografts to radiation therapy (RT). METHODS AND MATERIALS: Low passage head and neck squamous cancer cells (UT14) were injected to the flanks of female nu/nu mice to generate xenografts. After tumors reached a size of 500 mm(3) they were treated with either sham RT or 15 Gy in 1 fraction. At different time points, days 3, 9, and 16 for controls and days 4, 7, 12, 21, 30, and 40 after irradiation, 2 to 3 mice were assessed with dynamic FDG-PET acquisition over 2 hours. Immediately after the FDG-PET the tumors were harvested for global gene expression analysis and immunohistochemical evaluation of GLUT1 and HK2. Different analytic parameters were used to process the dynamic PET data. RESULTS: Radiation had no effect on key genes involved in FDG uptake and metabolism but did alter other genes in the HIF1α and glucose transport-related pathways. In contrast to the lack of effect on gene expression, changes in the protein expression patterns of the key genes GLUT1/SLC2A1 and HK2 were observed after radiation treatment. The changes in GLUT1 protein expression showed some correlation with dynamic FDG-PET parameters, such as the kinetic index. CONCLUSION: (18)F-fluorodeoxyglucose positron emission tomography changes after RT would seem to represent an altered metabolic state and not a direct effect on the key genes regulating FDG uptake and metabolism.

Gene expression changes associated with the progression of intraductal papillary mucinous neoplasms.

OBJECTIVES: The diagnosis of high-grade intraductal papillary mucinous neoplasm (IPMN) is difficult to distinguish from low-grade IPMN. The aim of this study was to identify potential markers for the discrimination of high-grade and invasive (HgInv) IPMN from low- and moderate-grade dysplasia IPMN. METHODS: Laser capture microdissection was used to isolate distinct foci of low-grade, moderate-grade, high-grade, and invasive IPMN from paraffin-embedded archival tissue from 14 patients who underwent resection for IPMN. Most samples included multiple grades in the same specimen. Affymetrix Human Exon microarrays were used to compare low- and moderate-grade dysplasia IPMN with HgInv IPMN. RESULTS: Sixty-two genes were identified as showing significant changes in expression (P ≤ 0.05 and a 2-fold cutoff), including up-regulation of 41 in HgInv IPMN. Changes in gene expression are associated with biological processes related to malignant behavior including cell motion, cell proliferation, response to hypoxia, and epithelial-to-mesenchymal transition. In addition, altered signaling in several transforming growth factor ß-related pathways was exhibited in the progression of IPMN to malignancy. CONCLUSIONS: This study identifies a set of genes associated with the progression of IPMN to malignancy. These genes are potential markers that could be used to identify IPMN requiring surgical resection.