Endometrial cancer risk has been associated with reproductive factors (age at menarche, age at menopause, parity, age at first and last birth, time since last birth and use of oral contraceptives (OCs)]. However, these factors are closely interrelated and whether they act independently still requires clarification. We conducted a study to examine the association of menstrual and reproductive variables with the risk of endometrial cancer among the European Prospective Investigation into Cancer and Nutrition (EPIC). Among the 302,618 women eligible for the study, 1,017 incident endometrial cancer cases were identified. A reduction in endometrial cancer risk was observed in women with late menarche, early menopause, past OC use, high parity and a shorter time since last full‐term pregnancy (FTP). No association was observed for duration of breast feeding after adjustment for number of FTP or for abortion (spontaneous or induced). After mutual adjustment, late age at menarche, early age at menopause and duration of OC use showed similar risk reductions of 7–8% per year of menstrual life, whereas the decreased risk associated with cumulative duration of FTPs was stronger (22% per year). In conclusion, our findings confirmed a reduction in risk of endometrial cancer with factors associated with a lower cumulative exposure to estrogen and/or higher exposure to progesterone, such as increasing number of FTPs and shorter menstrual lifespan and, therefore, support an important role of hormonal mechanisms in endometrial carcinogenesis.
Lipophilic statins purportedly exert anti-tumoral effects on breast cancer by decreasing proliferation and increasing apoptosis. HMG-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate pathway, is the target of statins. However, data on statin-induced effects on HMGCR activity in cancer are limited. Thus, this pre-operative study investigated statin-induced effects on tumor proliferation and HMGCR expression while analyzing HMGCR as a predictive marker for statin response in breast cancer treatment. The study was designed as a window-of-opportunity trial and included 50 patients with primary invasive breast cancer. High-dose atorvastatin (i.e., 80 mg/day) was prescribed to patients for 2 weeks before surgery. Pre- and post-statin paired tumor samples were analyzed for Ki67 and HMGCR immunohistochemical expression. Changes in the Ki67 expression and HMGCR activity following statin treatment were the primary and secondary endpoints, respectively. Up-regulation of HMGCR following atorvastatin treatment was observed in 68 % of the paired samples with evaluable HMGCR expression (P = 0.0005). The average relative decrease in Ki67 expression following atorvastatin treatment was 7.6 % (P = 0.39) in all paired samples, whereas the corresponding decrease in Ki67 expression in tumors expressing HMGCR in the pre-treatment sample was 24 % (P = 0.02). Furthermore, post-treatment Ki67 expression was inversely correlated to post-treatment HMGCR expression (rs = -0.42; P = 0.03). Findings from this study suggest that HMGCR is targeted by statins in breast cancer cells in vivo, and that statins may have an anti-proliferative effect in HMGCR-positive tumors. Future studies are needed to evaluate HMGCR as a predictive marker for the selection of breast cancer patients who may benefit from statin treatment.
Several prospective studies have shown a moderate positive association between increasing circulating insulin‐like growth factor‐I (IGF‐I) levels and colorectal cancer risk. However, the associations were often statistically nonsignificant, and the relationship of cancer risk with IGF‐I's major binding protein, IGFBP‐3, showed major discrepancies between studies. We investigated the association of colorectal cancer risk with serum IGF‐I, total and intact IGFBP‐3, in a case‐control study nested within the EPIC cohort (1,121 cases of colorectal cancer and 1,121 matched controls). Conditional logistic regression was used to adjust for possible confounders. Our present study results were combined in a meta‐analysis with those from 9 previous prospective studies to examine the overall evidence for a relationship of prediagnostic serum IGF‐I with colorectal cancer risk. In the EPIC study, serum concentrations of IGF‐I and IGFBP‐3 showed no associations with risk of colorectal cancer overall. Only in subgroup analyses did our study show moderate positive associations of IGF‐I levels with risk, either among younger participants only (and only for colon cancer) or among participants whose milk intakes were in the lowest tertile of the population distribution (RR for an increase of 100 ng/ml = 1.43 [95% CI = 1.13–1.93]). Nevertheless, in the meta‐analysis a modest positive association remained between serum IGF‐I and colorectal cancer risk overall (RR = 1.07 [1.01–1.14] for 1 standard deviation increase in IGF‐I). Overall, data from our present study and previous prospective studies combined indicate a relatively modest association of colorectal cancer risk with serum IGF‐I.
The epidemiological evidence for an obesity-cancer association is solid, whereas the association between obesity-associated lipoprotein levels and cancer is less evident. We investigated circulating levels of Apolipoprotein A1 (ApoA1), Apolipoprotein B (ApoB), LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C) and association to risk of overall cancer and common cancer forms. The Malm€ o Diet and Cancer Study, a population-based prospective cohort study, enrolled 17,035 women and 11,063 men (1991)(1992)(1993)(1994)(1995)(1996). Incident cancer cases were ascertained by record linkage with the Swedish Cancer Registry until end of follow-up, January 1, 2012. Baseline serum levels of ApoA1 and ApoB were analyzed for the entire cohort and HDL-C and LDL-C levels in 5,281 participants. Hazard ratios, with 95% confidence interval, were calculated using Cox's proportional hazards analysis. In the entire cohort, none of the exposures were related to overall cancer risk (HR adj ApoA1 5 0.98, 95%CI: 0.95,1.01; HR adj ApoB 5 1.01, 95%CI: 0.98-1.04). Among men, ApoB was positively associated with cancer risk (HR adj ApoB 5 1.06, 95%CI: 1.01,1.10). Female breast cancer risk was inversely associated with ApoB (HR adj 5 0.92, 95%CI: 0.86,0.99). Among both genders, ApoA1 was inversely associated with lung cancer risk (HR adj 5 0.88, 95%CI: 0.80,0.97), whereas high ApoB increased lung cancer risk (HR adj 5 1.08, 95%CI: 0.99,1.18). Colorectal cancer risk was increased with high ApoB (HR adj 5 1.08, 95%CI: 1.01,1.16) among both genders. Apolipoprotein levels were not associated with prostate cancer incidence. Circulating levels of apolipoproteins are associated with overall cancer risk in men and across both genders with breast, lung and colorectal cancer risk. Validation of these findings may facilitate future primary prevention strategies for cancer.Cancer incidence has increased continuously over time forcing action to be taken at all stages of prevention. 1 In particular, improved primary prevention of cancer requires identification of risk markers, preferentially in drug and lifestyle modifiable systems. 1,2 Within the field of cardiovascular disease (CVD), development of risk markers has been
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