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. Keywords: Microdissected tissue analysis
Project description:BackgroundAfrican-American breast cancer patients experience higher mortality rates than European-American patients despite having a lower incidence of the disease. We tested the hypothesis that intrinsic differences in the tumor biology may contribute to this cancer health disparity.Methods and resultsUsing laser capture microdissection, we examined genome-wide mRNA expression specific to tumor epithelium and tumor stroma in 18 African-American and 17 European-American patients. Numerous genes were differentially expressed between these two patient groups and a two-gene signature in the tumor epithelium distinguished between them. To identify the biological processes in tumors that are different by race/ethnicity, Gene Ontology and disease association analyses were performed. Several biological processes were identified which may contribute to enhanced disease aggressiveness in African-American patients, including angiogenesis and chemotaxis. African-American tumors also contained a prominent interferon signature. The role of angiogenesis in the tumor biology of African-Americans was further investigated by examining the extent of vascularization and macrophage infiltration in an expanded set of 248 breast tumors. Immunohistochemistry revealed that microvessel density and macrophage infiltration is higher in tumors of African-Americans than in tumors of European-Americans. Lastly, using an in silico approach, we explored the potential of tailored treatment options for African-American patients based on their gene expression profile. This exploratory approach generated lists of therapeutics that may have specific antagonistic activity against tumors of African-American patients, e.g., sirolimus, resveratrol, and chlorpromazine in estrogen receptor-negative tumors.ConclusionsThe gene expression profiles of breast tumors indicate that differences in tumor biology may exist between African-American and European-American patients beyond the knowledge of current markers. Notably, pathways related to tumor angiogenesis and chemotaxis could be functionally different in these two patient groups.
Project description:PurposeThe aim of this study was to compare the frequency of ERG rearrangement, PTEN deletion, SPINK1 overexpression, and SPOP mutation in prostate cancer in African American and Caucasian men.Experimental designDominant tumor nodules from radical prostatectomy specimens of 105 African American men (AAM) were compared with 113 dominant nodules from Caucasian men (CaM). Clinical and pathologic characteristics of the two groups were similar. SPINK1 overexpression was evaluated by immunohistochemistry, ERG rearrangement and PTEN deletion by FISH, and SPOP mutation by Sanger sequencing.ResultsERG rearrangement was identified in 48 of 113 tumors (42.5%) in CaM and 29 of 105 tumors (27.6%) in AAM (P = 0.024). PTEN deletion was seen in 19 of 96 tumors (19.8%) in CaM and 7 of 101 tumors (6.9%) in AAM (P = 0.011). SPINK1 overexpression was present in 9 of 110 tumors (8.2%) in CaM and 25 of 105 tumors (23.4%) in AAM (P = 0.002). SPOP mutation was identified in 8 of 78 (10.3%) tumors in CaM and 4 of 88 (4.5%) tumors in AAM (P = 0.230). When adjusted for age, body mass index, Gleason score, and pathologic stage, ERG rearrangement and SPINK1 overexpression remain significantly different (P = 0.018 and P = 0.008, respectively), and differences in PTEN deletion and SPOP mutation approach significance (P = 0.061 and P = 0.087, respectively).ConclusionsSignificant molecular differences exist between prostate cancers in AAM and CaM. SPINK1 overexpression, an alteration associated with more aggressive prostate cancers, was more frequent in AAM, whereas ERG rearrangement and PTEN deletion were less frequent in this cohort. Further investigation is warranted to determine whether these molecular differences explain some of the disparity in incidence and mortality between these two ethnic groups.
Project description:Prostate cancer is the most common non-skin cancer and the second leading cause of cancer-related death for men in the United States. Prostate cancer incidence and associated mortality are highest in African American men in comparison to other races. The observed differences in incidence and disease aggressiveness at presentation support a potential role for different pathways of prostate carcinogenesis between African American and Caucasian men. This review focuses on some of the recent molecular biology discoveries, which have been investigated in prostate carcinogenesis and their likely contribution to the known discrepancies across race and ethnicity. Key discussion points include the androgen receptor gene structure and function, genome-wide association studies and epigenetics. The new observations of the ethnic differences of the ERG oncogene, the most common prostate cancer gene, are providing new insights into ERG based stratification of prostate cancers in the context of ethnically diverse patient populations. This rapidly advancing knowledge has the likely potential to benefit clinical practice. Current and future work will improve the ability to sub-type prostate cancers by molecular alterations and lead to targeted therapy against this common malignancy.
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.
Project description:ObjectiveAfrican American men have higher prostate cancer incidence rates than White men, for reasons not completely understood. This review summarizes the existing literature of race-specific associations between risk factors and prostate cancer in order to examine whether associations differ.MethodsWe reviewed epidemiologic studies published between January 1970 and December 2008 that reported race-specific effect estimates. We focused mainly on modifiable risk factors related to lifestyle and health. A total of 37 articles from 21 study populations met our inclusion criteria.ResultsWe found no evidence of racial differences in associations between prostate cancer and alcohol intake, tobacco use, and family history of prostate cancer. Research suggests that a modest positive association may exist between height and prostate cancer risk (all prostate cancer and advanced prostate cancer) among Whites only. No clear patterns were observed for associations with physical activity, weight/body mass index, dietary factors, occupational history, sexual behavior, sexually transmissible infections, and other health conditions.DiscussionOur results suggest few differences in prostate cancer risk factors exist between racial groups and underscore areas where additional research is needed. Future studies should enroll higher numbers of African American participants and report results for advanced prostate cancer.
Project description:BackgroundPrior research shows between-race differences in women's knowledge and emotions related to having dense breasts, thus suggesting that between-race differences in behavioral decision-making following receipt of breast density (BD) notifications are likely. Guided by the theory of planned behavior, this study examined differences in emotion-related responses (i.e., anxiety, worry, confusion) and behavioral cognition (e.g., intentions, behavioral attitudes) following receipt of BD notifications among African American (AA) and European American (EA) women. This study also examined whether race-related perceptions (i.e., discrimination, group-based medical mistrust), relevant knowledge and socioeconomic status (SES) explained the between race differences.MethodMichigan women (N = 457) who presented for routine screening mammogram and had dense breasts, no prior breast cancer diagnoses, and had screen-negative mammograms were recruited from July, 2015 to March 2016. MANOVA was used to examine between race differences in psychological responses (i.e., emotional responses and behavioral cognition), and a multi-group structural regression model was used to examine whether race-related constructs, knowledge and SES mediated the effect of race on emotional responses and behavioral cognition. Prior awareness of BD was accounted for in all analyses.ResultsAA women generally reported more negative psychological responses to receiving BD notifications regardless of prior BD awareness. AA women had more favorable perceptions related to talking to their physicians about the BD notifications. Generally, race-related perceptions, SES, and related knowledge partially accounted for the effect of race on psychological response. Race-related perceptions and SES partially accounted for the differences in behavioral intentions. Between-race differences in emotional responses to BD notifications did not explain differences in women's intentions to discuss BD notifications with their physicians.ConclusionsFuture examinations are warranted to examine whether there are between-race differences in actual post-BD notification behaviors and whether similar race-related variables account for differences.
Project description:African-American (AA) men have both a higher incidence and significantly higher mortality rates from prostate cancer (PCa) than European American (EA) men. In this study we have carried out a detailed analysis of both CNAs and gene expression changes in PCas from AA men compared to their matched benign tissues. We have identified MNX1 as a novel androgen regulated oncogene that is upregulated to a greater degree in AA PCa compared to EA PCa. Furthermore, RGS12 is a novel tumor suppressor on 4p16.3 that is preferentially deleted in AA PCa which negatively regulates MNX1 expression.
Project description:Gene expression characteristics of primary prostate cancer tumors from African-Americans are substantially different as compared to European-American men
Project description:In prostate cancer, race/ethnicity is the highest risk factor after adjusting for age. African Americans have more aggressive tumors at every clinical stage of the disease, resulting in poorer prognosis and increased mortality. A major barrier to identifying crucial gene activity differences is heterogeneity, including tissue composition variation intrinsic to the histology of prostate cancer. We hypothesized that differences in gene expression in specific tissue types would reveal mechanisms involved in the racial disparities of prostate cancer. We examined 17 pairs of arrays for AAs and Caucasians that were formed by closely matching the samples based on the known tissue type composition of the tumors. Using pair-wise t-test we found significantly altered gene expression between AAs and CAs. Independently, we performed multiple linear regression analyses to associate gene expression with race considering variation in percent tumor and stroma tissue. The majority of differentially expressed genes were associated with tumor-adjacent stroma rather than tumor tissue. Extracellular matrix, integrin family and signaling mediators of the epithelial-to-mesenchymal transition (EMT) pathways were all downregulated in stroma of AAs. Using MetaCore (GeneGo) analysis, we observed that 35% of significant (p < 10(-3)) pathways identified EMT and 25% identified immune response pathways especially for interleukins-2, -4, -5, -6, -7, -10, -13, -15 and -22 as the major changes. Our studies reveal that altered immune and EMT processes in tumor-adjacent stroma may be responsible for the aggressive nature of prostate cancer in AAs.