Jackilen Shannon

Dr. Jackilen Shannon


Research Focus & Metrics

Academic Career Length

25Years (2002-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 August 2005 in American Journal of Epidemiology
Verified
Journal Article
Open access
PDF file
JSJackilen Shannon
Jackilen Shannon
STSelome Tewoderos
Selome Tewoderos
MGMark Garzotto
Mark Garzotto
TBTomasz M. Beer
Tomasz M. Beer
RDRhianna Derenick
Rhianna Derenick
PFPaige E. Farris
Paige E. Farris
Observational studies have shown that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) use may be associated with reduced cancer risk. The purpose of this case-control study was to elucidate the association between statin use and prostate cancer risk. Prostate cancer cases (n = 100), recruited upon referral for prostate biopsy, and frequency age-matched, prostate-specific antigen-normal clinic controls (n = 202) were recruited from the Portland, Oregon, Veterans Affairs Medical Center. Information on any use of statins from May 1997 through August 2004 was obtained from an electronic pharmacy database. Days of use, type of statin, dose, and prescription changes were recorded. Duration and intensity were calculated for each statin type on the basis of days of use and prescribed dose. Thirty-six percent of cases and 49 percent of controls had a record of any statin use. Following adjustment for other potential risk factors, statin use was associated with a significant reduction in prostate cancer risk (odds ratio = 0.38, 95% confidence interval: 0.21, 0.69). Furthermore, in analyses stratified by Gleason score, the inverse association with statin use was maintained only among men with Gleason scores of ≥7 (odds ratio = 0.24, 95% confidence interval: 0.11, 0.53). The results of this case-control study suggest that statins may reduce the risk of total prostate cancer and, specifically, more aggressive prostate cancer.

1 December 2015 in Cancer Prevention Research
Verified
Journal Article
Closed access
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LALauren L. Atwell
Lauren L. Atwell
ZZZhenzhen Zhang
Zhenzhen Zhang
MMMotomi Mori
Motomi Mori
PFPaige E. Farris
Paige E. Farris
JVJohn T. Vetto
John T. Vetto
JSJackilen Shannon
Jackilen Shannon
Epidemiologic studies suggest a protective effect of cruciferous vegetables on breast cancer. Sulforaphane (SFN), an active food component derived from crucifers, has been shown to be effective in breast cancer chemoprevention. This study evaluated the chemopreventive effect of SFN on selective biomarkers from blood and breast tissues. In a 2- to 8-week double-blinded, randomized controlled trial, 54 women with abnormal mammograms and scheduled for breast biopsy were randomized to consume a placebo or a glucoraphanin (GFN) supplement providing SFN (n = 27). Plasma and urinary SFN metabolites, peripheral blood mononuclear cell (PBMC) histone deacetylase (HDAC) activity, and tissue biomarkers (H3K18ac, H3K9ac, HDAC3, HDAC6, Ki-67, p21) were measured before and after the intervention in benign, ductal carcinoma in situ, or invasive ductal carcinoma breast tissues. Within the supplement group, Ki-67 (P = 0.003) and HDAC3 (P = 0.044) levels significantly decreased in benign tissue. Pre-to-postintervention changes in these biomarkers were not significantly different between treatment groups after multiple comparison adjustment. GFN supplementation was associated with a significant decrease in PBMC HDAC activity (P = 0.04). No significant associations were observed between SFN and examined tissue biomarkers when comparing treatment groups. This study provides evidence that GFN supplementation for a few weeks is safe but may not be sufficient for producing changes in breast tissue tumor biomarkers. Future studies employing larger sample sizes should evaluate alternative dosing and duration regimens to inform dietary SFN strategies in breast cancer chemoprevention. Cancer Prev Res; 8(12); 1184–91. ©2015 AACR.

6 January 2018 in BMC Cancer
Verified
Journal Article
Open access
PDF file
MDMelinda M. Davis
Melinda M. Davis
MFMichele Freeman
Michele Freeman
JSJackilen Shannon
Jackilen Shannon
GCGloria Coronado
Gloria Coronado
KSKurt C. Stange
Kurt C. Stange
DBDavid I. Buckley
David I. Buckley
Interventions to improve fecal testing for colorectal cancer (CRC) exist, but are not yet routine practice. We conducted this systematic review to determine how implementation strategies and contextual factors influenced the uptake of interventions to increase Fecal Immunochemical Tests (FIT) and Fecal Occult Blood Testing (FOBT) for CRC in rural and low-income populations in the United States. We searched Medline and the Cochrane Library from January 1998 through July 2016, and Scopus and clinicaltrials.gov through March 2015, for original articles of interventions to increase fecal testing for CRC. Two reviewers independently screened abstracts, reviewed full-text articles, extracted data and performed quality assessments. A qualitative synthesis described the relationship between changes in fecal testing rates for CRC, intervention components, implementation strategies, and contextual factors. A technical expert panel of primary care professionals, health system leaders, and academicians guided this work. Of 4218 citations initially identified, 27 unique studies reported in 29 publications met inclusion criteria. Studies were conducted in primary care (n = 20, 74.1%), community (n = 5, 18.5%), or both (n = 2, 7.4%) settings. All studies (n = 27, 100.0%) described multicomponent interventions. In clinic based studies, components that occurred most frequently among the highly effective/effective study arms were provision of kits by direct mail, use of a pre-addressed stamped envelope, client reminders, and provider ordered in-clinic distribution. Interventions were delivered by clinic staff/community members (n = 10, 37.0%), research staff (n = 6, 22.2%), both (n = 10, 37.0%), or it was unclear (n = 1, 3.7%). Over half of the studies lacked information on training or monitoring intervention fidelity (n = 15, 55.6%). Studies to improve FIT/FOBT in rural and low-income populations utilized multicomponent interventions. The provision of kits through the mail, use of pre-addressed stamped envelopes, client reminders and in-clinic distribution appeared most frequently in the highly effective/effective clinic-based study arms. Few studies described contextual factors or implementation strategies. More robust application of guidelines to support reporting on methods to select, adapt and implement interventions can help end users determine not just which interventions work to improve CRC screening, but which interventions would work best in their setting given specific patient populations, clinical settings, and community characteristics. In accordance with PRISMA guidelines, our systematic review protocol was registered with PROSPERO, the international prospective register of systematic reviews, on April 16, 2015 (registration number CRD42015019557 ).

1 August 2017 in Preventive Medicine
Verified
Journal Article
Closed access
MDMelinda M. Davis
Melinda M. Davis
SRStephanie Renfro
Stephanie Renfro
RPRobyn Pham
Robyn Pham
KLKristen Hassmiller Lich
Kristen Hassmiller Lich
JSJackilen Shannon
Jackilen Shannon
SWStephanie B Wheeler
Stephanie B Wheeler

1 April 2007 in The American Journal of Clinical Nutrition
Verified
Journal Article
Open access
PDF file
JSJackilen Shannon
Jackilen Shannon
IKIrena B King
Irena B King
RMRachel Moshofsky
Rachel Moshofsky
JLJohanna W Lampe
Johanna W Lampe
DGDao Li Gao
Dao Li Gao
DTDavid B Thomas
David B Thomas
Background: The role of individual fatty acids in the development and progression of breast cancer is unclear. Although in vitro and animal experiments have supported an inverse association between intake of long chain n−3 fatty acids [primarily eicosapentaenoic acid (EPA) and docosahexaenoic acid] and breast cancer risk, findings from population studies are inconsistent. Recent studies have also shown associations between the ratio of saturated to monounsaturated fatty acids (SI) and breast cancer risk. The SI reflects the activity of several genes involved in lipid metabolism, including fatty acid synthase and steroyl coenzyme-A desaturase, that have been shown to be overexpressed in breast cancer. Objective: The purpose of this analysis was to determine the association between erythrocyte fatty acid concentrations and breast cancer risk among women participating in a randomized trial of breast self-examination in Shanghai, China. Design: We conducted a case-control study. Erythrocyte fatty acid concentrations were determined in specimens from 322 women with histologically confirmed breast cancer and 1030 frequency age-matched control women. Results: We report a significant direct association among palmitic, γ-linolenic, palmitoleic, and vaccenic acids and risk of breast cancer. Total n−3 fatty acids, EPA, and the SI for palmitic to palmitoleic acid were associated with significantly lower risk of breast cancer. Conclusion: Our results support a protective effect of n−3 fatty acids on breast cancer risk and provide additional evidence for the importance of evaluating the ratio of fatty acids when evaluating diet and breast cancer risk.

1 June 2019 in Nutrition and Cancer
Verified
Journal Article
Closed access
ZZZhenzhen Zhang
Zhenzhen Zhang
MGMark Garzotto
Mark Garzotto
EDEdward Davis
Edward Davis
MMMotomi Mori
Motomi Mori
WSWesley A. Stoller
Wesley A. Stoller
JSJackilen Shannon
Jackilen Shannon
Previous studies suggest compounds such as sulforaphane (SFN) derived from cruciferous vegetables may prevent prostate cancer development and progression. This study evaluated the effect of broccoli sprout extract (BSE) supplementation on blood histone deacetylase (HDAC) activity, prostate RNA gene expression, and tissue biomarkers (histone H3 lysine 18 acetylation (H3K18ac), HDAC3, HDAC6, Ki67, and p21). A total of 98 men scheduled for prostate biopsy were allocated into either BSE (200 µmol daily) or a placebo in our double-blind, randomized controlled trial. We used nonparametric tests to evaluate the differences of blood HDAC activity and prostate tissue immunohistochemistry biomarkers between treatment groups. Further, we performed RNA-Seq analysis on the prostate biopsies and identified 40 differentially expressed genes correlated with BSE treatment, including downregulation of two genes previously implicated in prostate cancer development, AMACR and ARLNC1. Although urine and plasma SFN isothiocyanates and individual SFN metabolites were statistically higher in the treatment group, our results did not show a significant difference in HDAC activity or prostate tissue biomarkers. This study indicates BSE supplementation correlates with changes in gene expression but not with several other prostate cancer biomarkers. More research is required to fully understand the chemopreventive effects of BSE supplementation on prostate cancer.