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African American esophageal squamous cell carcinoma expression profile reveals loss of detox networks

ABSTRACT: Esophageal carcinoma is the third most common gastrointestinal malignancy worldwide and is generally unresponsive to therapy. African Americans have an increased risk for esophageal squamous cell cancer (ESCC), the subtype that shows marked variation in geographic frequency. To identify key genes involved in ESC carcinogenesis in African Americans we conducted microarray expression profiling and found a significant dysregulation of genes encoding stress response and drug-metabolizing enzymes, mainly in NRF2 pathway. The involvement of NRF2 mediated oxidative damage represent a key step in the evolution of African American ESCC. Loss of activity of these enzymes would confer increased sensitivity of esophageal cells to xenobiotics, such as alcohol and tobacco smoke, and may account for the high incidence of ESCC in this ethnic group. The differential expression profile also indicates an inflammatory component and tissue regeneration in ESCC tumorigenesis. Together, these findings suggest a remarkable interplay of genetic and environmental factors in the pathogenesis of African American ESCC.

ORGANISM(S): Homo sapiens

PROVIDER: GSE77861 | GEO | 2017/08/15

SECONDARY ACCESSION(S): PRJNA311754

REPOSITORIES: GEO

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Project description:The incidence and mortality rates of prostate cancer are significantly higher in African-American men when compared to European-American men. We tested the hypothesis that differences in tumor biology contribute to this survival health disparity. Using microarray technology, we obtained gene expression profiles of primary prostate tumors resected from 33 African-American and 36 European-American patients. These tumors were matched on clinical parameters. We also evaluated 18 non-tumor prostate tissues from 7 African-American and 11 European-American patients. The resulting datasets were analyzed for expression differences on the gene and pathway level comparing African-American with European-American patients. Our analysis revealed a significant number of genes, e.g., 162 transcripts at a false-discovery rate less than 5%, to be differently expressed between African-American and European-American patients. Using a disease association analysis, we identified a common relationship of these transcripts with autoimmunity and inflammation. These findings were corroborated on the pathway level with numerous differently expressed genes clustering in immune response, stress response, cytokine signaling, and chemotaxis pathways. Furthermore, a two-gene tumor signature was identified that accurately differentiated between African-American and European-American patients. This finding was confirmed in a blinded analysis of a second sample set. In conclusion, the gene expression profiles of prostate tumors indicate prominent differences in tumor immunobiology between African-American and European-American men. The profiles portray the existence of a distinct tumor microenvironment in these two patient groups. Experiment Overall Design: A total of 69 fresh-frozen prostate tumors were obtained from the NCI Cooperative Prostate Cancer Tissue Resource (CPCTR) and the Department of Pathology at the University of Maryland (UMD). All tumors were resected adenocarcinomas that had not received any therapy prior to prostatectomy. The macro-dissected CPCTR tumor specimens (n = 59) were reviewed by a CPCTR-associated pathologist, who confirmed the presence of tumor in the specimens. These tissues were collected between 2002 and 2004 at four different sites, with each site providing tissues from both African-American and European-American patients. Information on race/ethnicity (33 African-Americans and 36 European-Americans) was either extracted from medical records (CPCTR) or obtained through an epidemiological questionnaire in which race/ethnicity was self-reported (UMD). Only one patient, a European-American, was also Hispanic. Surrounding non-tumor prostate tissue was collected from 18 of the recruited patients in this study. Of those, 7 were African-American men and 11 were European-American men. We also isolated total RNA from 10 needle biopsy specimens collected from patients at the National Naval Medical Center (one African-American and 9 European-Americans) that did not have prostate cancer. From those, we prepared two RNA pools, each representing 5 patients. Clinicopathological characteristics of the patients, including age at prostatectomy, histology, Gleason score, pathological stage, PSA at diagnosis, tumor size, extraprostatic extension, margin involvement, and seminal vesicle invasion were obtained from CPCTR. For UMD cases, this information was extracted from the medical and pathology records, if available. Written informed consent was obtained from all donors. Tissue collection and study design were approved by the institutional review boards of the participating institutions.

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African American esophageal squamous cell carcinoma expression profile reveals loss of detox networks

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