Association among Dietary Flavonoids, Flavonoid Subclasses and Ovarian Cancer Risk: A Meta-Analysis

Abstract

BackgroundPrevious studies have indicated that intake of dietary flavonoids or flavonoid subclasses is associated with the ovarian cancer risk, but presented controversial results. Therefore, we conducted a meta-analysis to derive a more precise estimation of these associations.MethodsWe performed a search in PubMed, Google Scholar and ISI Web of Science from their inception to April 25, 2015 to select studies on the association among dietary flavonoids, flavonoid subclasses and ovarian cancer risk. The information was extracted by two independent authors. We assessed the heterogeneity, sensitivity, publication bias and quality of the articles. A random-effects model was used to calculate the pooled risk estimates.ResultsFive cohort studies and seven case-control studies were included in the final meta-analysis. We observed that intake of dietary flavonoids can decrease ovarian cancer risk, which was demonstrated by pooled RR (RR = 0.82, 95% CI = 0.68–0.98). In a subgroup analysis by flavonoid subtypes, the ovarian cancer risk was also decreased for isoflavones (RR = 0.67, 95% CI = 0.50–0.92) and flavonols (RR = 0.68, 95% CI = 0.58–0.80). While there was no compelling evidence that consumption of flavones (RR = 0.86, 95% CI = 0.71–1.03) could decrease ovarian cancer risk, which revealed part sources of heterogeneity. The sensitivity analysis indicated stable results, and no publication bias was observed based on the results of Funnel plot analysis and Egger’s test (p = 0.26).ConclusionsThis meta-analysis suggested that consumption of dietary flavonoids and subtypes (isoflavones, flavonols) has a protective effect against ovarian cancer with a reduced risk of ovarian cancer except for flavones consumption. Nevertheless, further investigations on a larger population covering more flavonoid subclasses are warranted.

Phenotype-driven transitions in regulatory network structure

“…Comparing angiogenic to non-angiogenic subtypes of ovarian cancer, we found functional modules that were enriched in expected disease pathways like blood vessel development, interleukin production, and JAK-STAT signaling. We also found enrichment for less expected processes including nutritional pathways like flavonoid biosynthesis and triglyceride homeostasis, which have been speculated to be relevant for ovarian cancer, but for which the underlying molecular pathways are not known (36)(37)(38)45). These biological processes were specific to the angiogenic subtype and uniquely revealed by ALPACA; they could not be found through standard community detection in the individual angiogenic and non-angiogenic networks or in an edge-subtracted network, or by running ALPACA in reverse on the non-angiogenic network compared to the angiogenic network.…”

“…Module 4 was enriched for "flavonoid glucuronidation" and contains the UDP glucuronosyltransferases UGT2B15, UGT1A8, and UGT2B17, enzymes that can help metabolize flavonoids and regulate hormones. Studies have hinted that dietary intake of flavonoids may reduce the risk of ovarian cancer (36)(37)(38) but the association is not statistically robust, and the mechanism is unknown. Our results suggest that the UGT family of enzymes may mediate the connection between flavonoids and ovarian cancer.…”

Basic Studies on Chemopreventive Properties of Quercetin and Curcumin and Other Plant-origin Compounds in Ovarian Cancer Cells – A Mini-review

“…According to the current state of knowledge chemoprevention includes using agents that affect cell-cycle progression and apoptosis, signal transduction, oncogene activation, polyamine metabolism, angiogenesis, gap junctional intercellular communication, and more [6,7]. According to guidelines for cancer prevention published by the American Cancer Society Guidelines, one of the key lifestyle factors thought to modify cancer risk is a diet, especially that rich in plantorigin compounds [8][9][10][11]. Although nowadays natural therapies are being more and more often considered by physicians to be used even in cancer patients, together with targeted therapies, still little is known about their interaction with conventional chemotherapeutic agents.…”

“…Flavonoids with several functions in pathological processes of cancer are polyphenolic compounds with a basic benzo-γ-pyrone structure being widely distributed in all foods of plant origin such as fruit, vegetable, tea and wine [9,14,15]. Some studies indicate that the observed pharmacological activities of flavonoids on ovarian cancer may depend on their structure [9,12].…”

“…Some studies indicate that the observed pharmacological activities of flavonoids on ovarian cancer may depend on their structure [9,12]. Based on the range and structural complexity, flavonoids can be categorized into six major subclasses: flavones, isoflavones, flavonols, flavanones, anthocyanidins and flavan-3-ols [11,16], among which flavones, isoflavones and flavonols are reported in the highest amounts of consumption in the human diet and have biological activity in ovarian cancer [8,9,17,18].…”