Effect of Lipophilic and Hydrophilic Statins on Breast Cancer Risk in Thai Women: A Cross-sectional Study

Circulating lipids, lipid-lowering drug targets, and breast cancer risk: Comprehensive evidence from Mendelian randomization and summary data-based Mendelian randomization

BACKGROUND

Breast cancer (BC) is the most common and fatal cancer among women, yet the causal relationship between circulating lipids, lipid-lowering drugs, and BC remains unclear.

METHODS

Mendelian randomization (MR) and summary data-based MR (SMR) analysis are used to explore the causal relationship between plasma lipids, lipid-lowering drug targets, and BC.

RESULTS

The result of MR suggested that per mg/dL higher levels of LDL-C (OR = 1.045, FDR = 0.023), HDL-C (OR = 1.079, FDR = 0.003), TC (OR = 1.043, FDR = 0.026), and APOA-I (OR = 1.085, FDR = 2.64E-04) were associated with increased BC risk, while TG was associated with reduced BC risk (OR = 0.926, FDR = 0.003). Per mg/dL higher levels of HDL-C (OR = 1.080, FDR = 0.011) and APOA-I (OR = 1.083, FDR = 0.002) were associated with increased ER+BC risk, while TG was associated with reduced ER+BC risk (OR = 0.909, FDR = 0.002). For every per 1 mg/dL decrease in LDL, HMGCR (OR: 0.839; FDR = 0.016), NPC1L1 (OR: 0.702; FDR = 0.004), and PCSK9 (OR: 0.916; FDR = 0.026) inhibition were associated with reduced BC risk, whereas CETP inhibition (OR: 1.194; FDR = 0.026) was associated with increased BC risk. For every per 1 mg/dL decrease in LDL, HMGCR (OR: 0.822; FDR = 0.023), NPC1L1 (OR: 0.633; FDR = 2.37E-03), and APOB inhibition (OR: 0.816; FDR = 1.98E-03) were associated with decreased ER-BC risk, while CETP inhibition (OR: 1.465; FDR = 0.011) was associated with increased ER-BC risk. SMR analysis indicated that HMGCR was associated with increased BC risk (OR: 1.112; p = 0.044).

CONCLUSION

Lipids are associated with the BC risk, and lipid-lowering drugs targets HMGCR, NPC1L1, PCSK9, and APOB may be effective strategies for preventing BC. However, lipid-lowering drugs target CETP may potentially increase BC risk.

Role of Lipoproteins in the Pathophysiology of Breast Cancer

Breast cancer is one of the most common malignancies in women and the leading cause of cancer mortality. Hypercholesterolemia and obesity are potential risk factors for the incidence of breast cancer, and their detection can enhance cancer prevention. In this paper, we discuss the current state of investigations on the importance of lipoproteins, such as low denisity lipoproteins (LDL) and high density lipoproteins (HDL), and cholesterol transporters in the progression of breast cancer, and the therapeutic strategies to reduce breast cancer mortality. Although some research has been unsuccessful at uncovering links between the roles of lipoproteins and breast cancer risk, major scientific trials have found a straight link between LDL levels and incidence of breast cancer, and an inverse link was found between HDL and breast cancer development. Cholesterol and its transporters were shown to have significant importance in the development of breast cancer in studies on breast cancer cell lines and experimental mice models. Instead of cholesterol, 27-hydroxycholesterol, which is a cholesterol metabolite, is thought to promote propagation and metastasis of estrogen receptor-positive breast cancer cell lines. Alteration of lipoproteins via oxidation and HDL glycation are thought to activate many pathways associated with inflammation, thereby promoting cellular proliferation and migration, leading to metastasis while suppressing apoptosis. Medications that lower cholesterol levels and apolipoprotein A-I mimics have appeared to be possible therapeutic agents for preventing excessive cholesterol’s role in promoting the development of breast cancer.

Lipoproteins and cancer: The role of HDL-C, LDL-C, and cholesterol-lowering drugs

Cholesterol is an amphipathic sterol molecule that is vital for maintaining normal physiological homeostasis. It is a relatively complicated molecule with 27 carbons whose synthesis starts with 2-carbon units. This in itself signifies the importance of this molecule. Cholesterol serves as a precursor for vitamin D, bile acids, and hormones, including estrogens, androgens, progestogens, and corticosteroids. Although essential, high cholesterol levels are associated with cardiovascular and kidney diseases and cancer initiation, progression, and metastasis. Although there are some contrary reports, current literature suggests a positive association between serum cholesterol levels and the risk and extent of cancer development. In this review, we first present a brief overview of cholesterol biosynthesis and its transport, then elucidate the role of cholesterol in the progression of some cancers. Suggested mechanisms for cholesterol-mediated cancer progression are plentiful and include the activation of oncogenic signaling pathways and the induction of oxidative stress, among others. The specific roles of the lipoprotein molecules, high-density lipoprotein (HDL) and low-density lipoprotein (LDL), in this pathogenesis, are also reviewed. Finally, we hone on the potential role of some cholesterol-lowering medications in cancer.

Statin use and incidence and mortality of breast and gynecology cancer: A cohort study using the National Health Insurance claims database

Previous studies have reported inconsistent findings concerning the impact of statin use on cancer prevention. This study examined the association between statin use and cancer incidence and mortality related to breast and gynecologic cancers in South Korea. A population-based cohort study was conducted using the National Health Insurance claims database. Women aged 45-70 years old who had taken statins for at least 6 months were compared to statin non-users of the same age from January 2005 to June 2013. The primary outcomes were cancer incidence and mortality related to breast cancer, total gynecologic cancers, cervix uteri cancer, and ovarian cancer. Cox proportional hazards regression was conducted to calculate the adjusted hazard ratios (aHRs) and 95% confidence intervals (95% CIs). Out of 587 705 women, there were 3591 cases of breast cancer, 2239 cases of gynecologic cancers, and 565 breast and total gynecologic cancer deaths during 7.6 person-years. The aHRs for the association between the risk of each cancer and statin use were 0.88 (95% CI 0.79-0.97) for breast cancer and 0.83 (95% CI 0.67-0.99) for cervix uteri cancer. Statin use was associated with decreased breast cancer mortality (HR = 0.65, 95% CI 0.43-0.99) and total gynecologic cancer mortality (HR = 0.70, 95% CI 0.50-0.98). A dose-response relationship was only found for all-cancer mortality. Statin use for at least 6 months was significantly associated with a lower risk of breast and cervix uteri cancer incidence, and with lower mortality of breast and gynecologic cancers. Further research on these associations will be needed. This article is protected by copyright. All rights reserved.

Biological Significance of YAP/TAZ in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal types of cancer. Despite major advances in defining the molecular mutations driving PDAC, this disease remains universally lethal with an overall 5-year survival rate of only about 7–8%. Genetic alterations in PDAC are exemplified by four critical genes (KRAS, TP53, CDKN2A, and SMAD4) that are frequently mutated. Among these, KRAS mutation ranges from 88% to 100% in several studies. Hippo signaling is an evolutionarily conserved network that plays a key role in normal organ development and tissue regeneration. Its core consists of the serine/threonine kinases mammalian sterile 20-like kinase 1 and 2 (MST1/2) and large tumor suppressor 1 and 2. Interestingly, pancreas-specific MST1/2 double knockout mice have been reported to display a decreased pancreas mass. Many of the genes involved in the Hippo signaling pathway are recognized as tumor suppressors, while the Hippo transducers Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) are identified as oncogenes. By dephosphorylation, YAP and TAZ accumulate in the nucleus and interact with transcription factors such as TEA domain transcription factor-1, 2, 3, and 4. Dysregulation of Hippo signaling and activation of YAP/TAZ have been recognized in a variety of human solid cancers, including PDAC. Recent studies have elucidated that YAP/TAZ play a crucial role in the induction of acinar-to-ductal metaplasia, an initial step in the progression to PDAC, in genetically engineered mouse models. YAP and TAZ also play a key role in the development of PDAC by both KRAS-dependent and KRAS-independent bypass mechanisms. YAP/TAZ have become extensively studied in PDAC and their biological importance during the development and progression of PDAC has been uncovered. In this review, we summarize the biological significance of a dysregulated Hippo signaling pathway or activated YAP/TAZ in PDAC and propose a role for YAP/TAZ as a therapeutic target.

Medication use and mammographic breast density

PURPOSE

A dense breast on mammogram is a strong risk factor for breast cancer. Identifying factors that reduce mammographic breast density could thus provide insight into breast cancer prevention. Due to the limited number of studies and conflicting findings, we investigated the associations of medication use (specifically statins, aspirin, and ibuprofen) with mammographic breast density.

METHODS

We evaluated these associations in 775 women who were recruited during an annual screening mammogram at Washington University School of Medicine, St. Louis. We measured mammographic breast density using Volpara. We used multivariable-adjusted linear regressions to determine the associations of medication use (statins, aspirin, and ibuprofen) with mammographic breast density. Least squared means were generated and back-transformed for easier interpretation.

RESULTS

The mean age of study participants was 52.9 years. Statin use in the prior 12 months was not associated with volumetric percent density or dense volume, but was positively associated with non-dense volume. The mean volumetric percent density was 8.6% among statin non-users, 7.2% among women who used statins 1-3 days/week, and 7.3% among women who used statins ≥ 4 days/week (p trend = 0.07). The non-dense volume was 1297.1 cm³ among statin non-users, 1368.7 cm³ among women who used statins 1-3 days/week, and 1408.4 cm³ among those who used statins ≥ 4 days/week (p trend = 0.02). We did not observe statistically significant differences in mammographic breast density by aspirin or ibuprofen use.

CONCLUSION

Statin, aspirin, and ibuprofen use was not associated with volumetric percent density and dense volume, but statin use was positively associated with non-dense volume. Any potential associations of these medications with breast cancer risk are unlikely to be mediated through an effect on volumetric percent density.

Statin Type and Cancer Outcomes in Patients with Diabetes Type 2 and Solid Tumors

Objective

Type 2 diabetes mellitus (T2DM) affects 10% of Americans and is associated with an increased incidence of cancer. Statins are first-line cholesterol-lowering medications in the treatment of hyperlipidemia. Several studies have demonstrated a relationship between statin use and reduced cancer incidence. We examined the cancer benefits of statin subtypes, with specific attention to disease-free survival (DFS) and overall survival (OS).

Methods

This retrospective review included adults with T2DM diagnosed with solid tumors at Roswell Park Cancer Institute in Buffalo, NY, USA (2003-2010). Individuals with gestational diabetes, incomplete records, or diagnosed with rare solid tumors were excluded. Follow-up began at the date of diagnosis and ended with the first confirmed recurrence, death, or loss of contact. Demographics were assessed by Chi-square, Kaplan-Meier survival analyses, and Cox proportional hazards regression.

Findings

Overall, 1102 patients met inclusion criteria, 52.1% of the study participants were female, and 578 participants (52.5%) died during the follow-up period which ranged from 0 to 156 months. Hydrophilic statin use was associated with improved DFS at 5-year follow-up (41.0% vs. 36.9%, P = 0.0077) compared to lipophilic statin use. Multivariate regression revealed that hydrophilic statins were associated with improved DFS (hazard ratio [HR]: 0.706, 95% confidence interval [CI]: 0.526-0.947) and OS (HR: 0.685, 95% CI: 0.503-0.934). Pravastatin was associated with improved OS (HR: 0.674, 95% CI: 0.471-0.964).

Conclusion

In patients with T2DM and cancer, hydrophilic statins, and pravastatin in particular, are associated with improved DFS as well as OS. Further research examining the cancer-specific effects of hydrophilic and lipophilic statins is needed to better understand their beneficial effects.

LDL, HDL and endocrine-related cancer: From pathogenic mechanisms to therapies

Cholesterol is essential for a variety of functions in endocrine-related cells, including hormone and steroid production. We have reviewed the progress to date in research on the role of the main cholesterol-containing lipoproteins; low-density lipoprotein (LDL) and high-density lipoprotein (HDL), and their impact on intracellular cholesterol homeostasis and carcinogenic pathways in endocrine-related cancers. Neither LDL-cholesterol (LDL-C) nor HDL-cholesterol (HDL-C) was consistently associated with endocrine-related cancer risk. However, preclinical studies showed that LDL receptor plays a critical role in endocrine-related tumor cells, mainly by enhancing circulating LDL-C uptake and modulating tumorigenic signaling pathways. Although scavenger receptor type BI-mediated uptake of HDL could enhance cell proliferation in breast, prostate, and ovarian cancer, these effects may be counteracted by the antioxidant and anti-inflammatory properties of HDL. Moreover, 27-hydroxycholesterol a metabolite of cholesterol promotes tumorigenic processes in breast and epithelial thyroid cancer. Furthermore, statins have been reported to reduce the incidence of breast, prostate, pancreatic, and ovarian cancer in large clinical trials, in part because of their ability to lower cholesterol synthesis. Overall, cholesterol homeostasis deregulation in endocrine-related cancers offers new therapeutic opportunities, but more mechanistic studies are needed to translate the preclinical findings into clinical therapies.

Association between statin use and second cancer risk in breast cancer patients: a nationwide population-based cohort study

PURPOSE

Many studies have revealed that statin therapy reduced mortality in cancer patients, especially in breast cancer, but the effect for second cancer was unclear. We, therefore, performed a comparable cohort study to determine the risk of second cancer in breast cancer patients with statin therapy.

METHODS

Using claims data from Taiwan's National Health Insurance Program, this study enrolled newly diagnosed breast cancer patients from 2000 to 2007 with and without statin therapy as the statin (n = 1222) and nonstatin (n = 4888) cohorts, respectively. The nonstatin cohort was propensity score matched by cohort entry year, age, and randomly selected comorbidities. These two cohorts were followed up until the diagnosis of second cancer, death, or the end of 2011. Cox proportional hazard models were used to estimate the hazard ratios.

RESULTS

The statin cohort had a lower incidence rate than the nonstatin cohort for second cancer (7.37 vs. 8.36 per 1000 person-years), although the difference was not significant (adjusted hazard ratio [aHR] 0.90, 95% confidence interval [CI] 0.65-1.26). Compared with the nonstatin cohort, the second cancer risk was significantly higher for patients taking pravastatin (aHR 2.71, 95% CI 1.19-6.19) but lower for those receiving multiple statin treatment (aHR 0.45, 95% CI 0.25-0.81) and combined lipophilic and hydrophilic type of statin (aHR 0.42, 95% CI 0.20-0.89). The risk was lower for patients receiving a cumulative defined daily dose (cDDD) of > 430 (aHR 0.41, 95% CI 0.19-0.86).

CONCLUSION

This study showed that there is little association between statin use and second cancer risk in breast cancer patients.

HDL and LDL: Potential New Players in Breast Cancer Development

Breast cancer is the most prevalent cancer and primary cause of cancer-related mortality in women. The identification of risk factors can improve prevention of cancer, and obesity and hypercholesterolemia represent potentially modifiable breast cancer risk factors. In the present work, we review the progress to date in research on the potential role of the main cholesterol transporters, low-density and high-density lipoproteins (LDL and HDL), on breast cancer development. Although some studies have failed to find associations between lipoproteins and breast cancer, some large clinical studies have demonstrated a direct association between LDL cholesterol levels and breast cancer risk and an inverse association between HDL cholesterol and breast cancer risk. Research in breast cancer cells and experimental mouse models of breast cancer have demonstrated an important role for cholesterol and its transporters in breast cancer development. Instead of cholesterol, the cholesterol metabolite 27-hydroxycholesterol induces the proliferation of estrogen receptor-positive breast cancer cells and facilitates metastasis. Oxidative modification of the lipoproteins and HDL glycation activate different inflammation-related pathways, thereby enhancing cell proliferation and migration and inhibiting apoptosis. Cholesterol-lowering drugs and apolipoprotein A-I mimetics have emerged as potential therapeutic agents to prevent the deleterious effects of high cholesterol in breast cancer.

Contrasting effects of comorbidities on emergency colon cancer diagnosis: a longitudinal data-linkage study in England

BACKGROUND

One in three colon cancers are diagnosed as an emergency, which is associated with worse cancer outcomes. Chronic conditions (comorbidities) affect large proportions of adults and they might influence the risk of emergency presentations (EP).

METHODS

We aimed to evaluate the effect of specific pre-existing comorbidities on the risk of colon cancer being diagnosed following an EP rather than through non-emergency routes. The cohort study included 5745 colon cancer patients diagnosed in England 2005-2010, with individually-linked cancer registry, primary and secondary care data. In addition to multivariable analyses we also used potential-outcomes methods.

RESULTS

Colon cancer patients with comorbidities consulted their GP more frequently with cancer symptoms during the pre-diagnostic year, compared with non-comorbid cancer patients. EP occurred more frequently in patients with 'serious' or complex comorbidities (diabetes, cardiac and respiratory diseases) diagnosed/treated in hospital during the years pre-cancer diagnosis (43% EP in comorbid versus 27% in non-comorbid individuals; multivariable analysis Odds Ratio (OR), controlling for socio-demographic factors and symptoms: men OR = 2.40; 95% CI 2.0-2.9 and women OR = 1.98; 95% CI 1.6-2.4. Among women younger than 60, gynaecological (OR = 3.41; 95% CI 1.2-9.9) or recent onset gastro-intestinal conditions (OR = 2.84; 95% CI 1.1-7.7) increased the risk of EP. In contrast, primary care visits for hypertension monitoring decreased EPs for both genders.

CONCLUSIONS

Patients with comorbidities have a greater risk of being diagnosed with cancer as an emergency, although they consult more frequently with cancer symptoms during the year pre-cancer diagnosis. This suggests that comorbidities may interfere with diagnostic reasoning or investigations due to 'competing demands' or because they provide 'alternative explanations'. In contrast, the management of chronic risk factors such as hypertension may offer opportunities for earlier diagnosis. Interventions are needed to support the diagnostic process in comorbid patients. Appropriate guidelines and diagnostic services to support the evaluation of new or changing symptoms in comorbid patients may be useful.

Central role of Yes-associated protein and WW-domain-containing transcriptional co-activator with PDZ-binding motif in pancreatic cancer development

Pancreatic ductal adenocarcinoma (PDAC) remains a deadly disease with no efficacious treatment options. PDAC incidence is projected to increase, which may be caused at least partially by the obesity epidemic. Significantly enhanced efforts to prevent or intercept this cancer are clearly warranted. Oncogenic KRAS mutations are recognized initiating events in PDAC development, however, they are not entirely sufficient for the development of fully invasive PDAC. Additional genetic alterations and/or environmental, nutritional, and metabolic signals, as present in obesity, type-2 diabetes mellitus, and inflammation, are required for full PDAC formation. We hypothesize that oncogenic KRAS increases the intensity and duration of the growth-promoting signaling network. Recent exciting studies from different laboratories indicate that the activity of the transcriptional co-activators Yes-associated protein (YAP) and WW-domain-containing transcriptional co-activator with PDZ-binding motif (TAZ) play a critical role in the promotion and maintenance of PDAC operating as key downstream target of KRAS signaling. While initially thought to be primarily an effector of the tumor-suppressive Hippo pathway, more recent studies revealed that YAP/TAZ subcellular localization and co-transcriptional activity is regulated by multiple upstream signals. Overall, YAP has emerged as a central node of transcriptional convergence in growth-promoting signaling in PDAC cells. Indeed, YAP expression is an independent unfavorable prognostic marker for overall survival of PDAC. In what follows, we will review studies implicating YAP/TAZ in pancreatic cancer development and consider different approaches to target these transcriptional regulators.

Association of antidiabetic medication and statins with breast cancer incidence in women with type 2 diabetes

Purpose

To address the possible association between the use of metformin, other forms of antidiabetic medication (ADM) and statins with the incidence of breast cancer in women with type 2 diabetes (T2D).

Methods

Data were collected from a Finnish nationwide diabetes database (FinDM). The study cohort consisted of women diagnosed with T2D in 1996–2011 in Finland. In full-cohort analysis, Poisson regression was used to estimate hazard ratios (HRs) in relation to use of metformin, insulin, other forms of oral ADM and statins. In nested case–control analysis, up to 20 controls were matched for age and duration of diabetes to each case of breast cancer. Conditional logistic regression was used to estimate HRs in relation to medication use and cumulative use of different forms of ADM, and statins.

Results

2300 women were diagnosed with breast cancer during follow-up. No difference in breast cancer incidence was observed between metformin users [HR 1.02, 95% confidence interval (CI) 0.93–1.11] or statin users (HR 0.97, 95% CI 0.89–1.05) compared with non-users. In nested case–control analysis the results were similar. Use of insulin (HR 1.18, 95% CI 1.03–1.36) was associated with a slightly increased incidence of breast cancer.

Conclusions

No evidence of an association between the use of metformin or statins and the incidence of breast cancer in women with T2D was found. Among insulin users, a slightly higher incidence of breast cancer was observed.

Electronic supplementary material

The online version of this article (10.1007/s10549-019-05185-0) contains supplementary material, which is available to authorized users.

The relationship between statins and breast cancer prognosis varies by statin type and exposure time: a meta-analysis

PURPOSE

Breast cancer is the most common cancer in females and the leading cause of death worldwide. The effects of statins on breast cancer prognosis have long been controversial; thus, it is important to investigate the relationship between statin type, exposure time, and breast cancer prognosis. This study sought to explore the effect of statins, as well as the different effects of statin solubility and variable follow-up times, on breast cancer prognosis.

METHODS

We searched the MEDLINE (via PubMed), EMBASE (via OvidSP), Cochrane Library, and ISI Web of Knowledge databases using combinations of the terms "breast neoplasms[MeSH]," "statins" or "lipid-lowering drug," "prognosis" or "survival," or "mortality" or "outcome" with no limit on the publication date. We searched the databases between inception and October 15, 2016. Reference lists of the included studies and relevant reviews were also manually screened. The initial search identified 71 publications, and 7 of these studies, which included a total of 197,048 women, met the selection criteria. Two authors independently screened each study for inclusion and extracted the data. The data were analyzed using Stata/SE 11.0.

RESULTS

Overall statin use was associated with lower cancer-specific mortality and all-cause mortality, although the benefit appeared to be constrained by statin type and follow-up time. Lipophilic statins were associated with decreased breast cancer-specific and all-cause mortality; however, hydrophilic statins were weakly protective against only all-cause mortality and not breast cancer-specific mortality. Of note, one group with more than 4 years of follow-up did not show a significant correlation between statin use and cancer-specific mortality or all-cause mortality, whereas groups with less than 4 years of follow-up still showed the protective effect of statins against cancer-specific mortality and all-cause mortality.

CONCLUSIONS

Although statins can reduce breast cancer patient mortality, the benefit appears to be constrained by statin type and follow-up time. Lipophilic statins showed a strong protective function in breast cancer patients, whereas hydrophilic statins only slightly improved all-cause mortality. Finally, the protective effect of statins could only be observed in groups with less than 4 years of follow-up. These findings are meaningful in clinical practice, although some conclusions contradict conventional wisdom and will thus require further exploration.