Association between diabetes mellitus and adverse characteristics of breast cancer at presentation

Hyperglycemia-driven signaling bridges between diabetes and cancer

Growing epidemiological evidence indicates an association between obesity, type 2 diabetes, and certain cancers, suggesting the existence of common underlying mechanisms in these diseases. Frequent hyperglycemias in type 2 diabetes promote pro-inflammatory responses and stimulate intracellular metabolic flux which rewires signaling pathways and influences the onset and advancement of different types of cancers. Here, we review the provocative impact of hyperglycemia on a subset of interconnected signalling pathways that regulate (i) cell growth and survival, (ii) metabolism adjustments, (iii) protein function modulation in response to nutrient availability (iv) and cell fate and proliferation and which are driven respectively by PI3K (Phosphoinositide 3-kinase), AMPK (AMP-activated protein kinase), O-GlcNAc (O-linked N-acetylglucosamine) and Wnt/β-catenin. Specifically, we will elaborate on their involvement in glucose metabolism, inflammation, and cell proliferation, highlighting their interplay in the pathogenesis of diabetes and cancer. Furthermore, the influence of antineoplastic and antidiabetic drugs on the unbridled cellular pathways will be examined. This review aims to inspire the next molecular studies to understand how type 2 diabetes may lead to certain cancers. This will contribute to personalized medicine and direct better prevention strategies.

Incident diabetes among older Asian, Native Hawaiian, and Pacific Islander women with breast cancer

BACKGROUND

The risk of diabetes among Asian, Native Hawaiian, and Pacific Islander (ANHPI) women after breast cancer is unclear. This study estimated the risk of incident type II diabetes in older ANHPI and older non-Hispanic White (NHW) women with breast cancer from the US National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Medicare linked claims.

METHODS

A matched cohort of 7122 older ANHPI and 21 365 older NHW women with breast cancer were identified from SEER-Medicare between 2000 and 2017. To assess the risk of incident type II diabetes after breast cancer, hazard ratios (HRs) and 95% confidence intervals (95% CI) were estimated using the Cox proportional-hazards regression model.

RESULTS

During the mean 8 years of follow-up, 9.3% of older women with breast cancer developed incident type II diabetes. In comparison with older NHW women, older ANHPI women without a known history of diabetes had an elevated risk of diabetes after breast cancer, with strong associations observed for Pacific Islander (HR = 3.09, 95% CI = 1.43 to 6.67), Vietnamese (HR = 2.12, 95% CI = 1.33 to 2.36), and Filipino (HR = 2.02, 95% CI = 1.57 to 2.59) women with breast cancer, adjusting for potential confounders. Among ANHPI women with breast cancer, more baseline comorbidities and obesity were risk factors for developing incident type II diabetes.

CONCLUSION

ANHPI women diagnosed with breast cancer had an elevated risk of type II diabetes compared with older NHW women with breast cancer. Routine monitoring and management of diabetes are warranted in older ANHPI women with breast cancer.

Breast cancer and incidence of type 2 diabetes mellitus: a systematic review and meta-analysis

PURPOSE

Breast cancer and its treatments may increase the risk of type 2 diabetes (T2D). We conducted a systematic review and meta-analysis to investigate the association between breast cancer and the incidence of T2D overall, and according to breast cancer treatments.

METHODS

We searched PubMed, Embase and references of relevant papers for studies on breast cancer, breast cancer treatment, and subsequent T2D risk. Using random-effects models, we calculated effect estimates and associated 95% confidence intervals of the association between breast cancer, adjuvant breast cancer treatments (i.e., endocrine therapy (tamoxifen, aromatase inhibitors, and combined) and chemotherapy), and subsequent T2D. We used funnel plots to assess publication bias.

RESULTS

Among 15 eligible studies, 10 reported on T2D risk after breast cancer, chemotherapy, or endocrine therapy; five studies investigated more than one association. Compared with patients without breast cancer, those with breast cancer and those who received any endocrine therapy had elevated risk of incident T2D (EE = 1.23, 95% CI = 1.13-1.33 and EE = 1.23, 95% CI = 1.16-1.32, respectively). Among breast cancer patients only, the risk of T2D was higher for those who received tamoxifen compared with those who did not receive tamoxifen (EE = 1.28, 95% CI = 1.18-1.38). Due to few studies, analyses investigating T2D risk after treatment with aromatase inhibitors or chemotherapy were inconclusive.

CONCLUSION

Our findings suggest an elevated risk of T2D in breast cancer survivors, particularly after tamoxifen therapy. Further research is needed to determine the impact of aromatase inhibitors, and chemotherapy on the incidence of T2D after breast cancer.

Antitumoral activity of liraglutide, a new DNMT inhibitor in breast cancer cells in vitro and in vivo

Breast cancer (BC) is the most frequently diagnosed female cancer and second leading cause of death. Despite the discovery of many antineoplastic drugs for BC, the current therapy is not totally efficient. In this study, we investigated the potential of repurposing the well-known diabetes type II drug liraglutide to modulate epigenetic modifications in BC cells lines in vitro and in vivo via Ehrlich mice tumors models. The in vitro results revealed a significant reduction on cell viability, migration, DNMT activity and displayed lower levels of global DNA methylation in BC cell lines after liraglutide treatment. The interaction between liraglutide and the DNMT enzymes resulted in a decrease profile of DNA methylation for the CDH1, ESR1 and ADAM33 gene promoter regions and, consequently, increased their gene and protein expression levels. To elucidate the possible interaction between liraglutide and the DNMT1 protein, we performed an in silico study that indicates liraglutide binding in the catalytic cleft via hydrogen bonds and salt bridges with the interdomain contacts and disturbs the overall enzyme conformation. The in vivo study was also able to reveal that liraglutide and the combined treatment of liraglutide and paclitaxel or methotrexate were effective in reducing tumor growth. Moreover, the modulation of CDH1 and ADAM33 mouse gene expression by DNA demethylation suggests a role for liraglutide in DNMT activity in vivo. Altogether, these results indicate that liraglutide may be further analysed as a new adjuvant treatment for BC.

Endocrine Therapy-related Endocrinopathies-Biology, Prevalence and Implications for the Management of Breast Cancer

Nearly 270,000 new breast cancer cases are predicted to be diagnosed in the USA in 2019 with more than 70% being estrogen receptor positive and treated using endocrine therapy. The suppression of estrogen biosynthesis or action via the use of ovarian suppression, aromatase inhibitors and selective estrogen receptor modulators/degraders, respectively, is effective in approximately 70% of women. The systemic inhibition of estrogen during breast cancer treatment is also associated with side effects due to the important endocrine functions of this steroid hormone, including its role in the maintenance of energy homeostasis and bone health. The current work will present perspectives of the impact of endocrine therapy from the point of view of breast medical oncology, endocrinology, and basic science.

Type 2 Diabetes, but Not Insulin (Analog) Treatment, Is Associated With More Advanced Stages of Breast Cancer: A National Linkage of Cancer and Pharmacy Registries

OBJECTIVE

To investigate whether women with type 2 diabetes (T2D) develop a more advanced stage of breast cancer and whether treatment with insulin (analogs) is associated with specific breast cancer characteristics.

RESEARCH DESIGN AND METHODS

For this nested case-control study, women with breast cancer diagnosed in 2002-2014 were selected from the linked Netherlands Cancer Registry-PHARMO Database Network (N = 33,377). T2D was defined as receiving two or more dispensings of noninsulin blood glucose-lowering drugs prior to breast cancer diagnosis. Women with T2D were matched to women without diabetes. Among women with T2D, insulin users and nonusers were compared. Multivariable ordinal logistic regression was used to investigate the association between T2D/insulin and breast cancer characteristics, including TNM classification (tumor size, lymph node status, metastasis), morphology, grade, estrogen receptor and progesterone receptor (PR), human epidermal growth factor receptor 2, and molecular subtype.

RESULTS

Women with T2D (n = 1,567) were more often diagnosed with a more advanced tumor stage (odds ratio 1.28 [95% CI 13-1.44]) and a higher grade (1.22 [1.08-1.39]) though less often with a PR-negative breast tumor (0.77 [0.67-0.89]) than women without diabetes (n = 6,267). No associations were found for the other breast cancer characteristics. Women with T2D using insulin (n = 388) were not diagnosed with different breast cancer characteristics compared with women with T2D not using insulin (n = 1,179).

CONCLUSIONS

Our study suggests that women with T2D are at increased risk to be diagnosed with a more aggressive type of breast cancer than women without diabetes. No evidence was found that the use of insulin (analogs) is associated with developing more advanced breast cancer tumors.

Diabetes and Breast Cancer Subtypes

Background

Women with diabetes have a worse survival after breast cancer diagnosis compared to women without diabetes. This may be due to a different etiological profile, leading to the development of more aggressive breast cancer subtypes. Our aim was to investigate whether insulin and non-insulin treated women with diabetes develop specific clinicopathological breast cancer subtypes compared to women without diabetes.

Methods and Findings

This cross-sectional study included randomly selected patients with invasive breast cancer diagnosed in 2000–2010. Stratified by age at breast cancer diagnosis (≤50 and >50 years), women with diabetes were 2:1 frequency-matched on year of birth and age at breast cancer diagnosis (both in 10-year categories) to women without diabetes, to select ~300 patients with tumor tissue available. Tumor MicroArrays were stained by immunohistochemistry for estrogen and progesterone receptor (ER, PR), HER2, Ki67, CK5/6, CK14, and p63. A pathologist scored all stains and revised morphology and grade. Associations between diabetes/insulin treatment and clinicopathological subtypes were analyzed using multivariable logistic regression. Morphology and grade were not significantly different between women with diabetes (n = 211) and women without diabetes (n = 101), irrespective of menopausal status. Premenopausal women with diabetes tended to have more often PR-negative (OR = 2.44(95%CI:1.07–5.55)), HER2-negative (OR = 2.84(95%CI:1.11–7.22)), and basal-like (OR = 3.14(95%CI:1.03–9.60) tumors than the women without diabetes, with non-significantly increased frequencies of ER-negative (OR = 2.48(95%CI:0.95–6.45)) and triple negative (OR = 2.60(95%CI:0.88–7.67) tumors. After adjustment for age and BMI, the associations remained similar in size but less significant. We observed no evidence for associations of clinicopathological subtypes with diabetes in postmenopausal women, or with insulin treatment in general.

Conclusions

We found no compelling evidence that women with diabetes, treated with or without insulin, develop different breast cancer subtypes than women without diabetes. However, premenopausal women with diabetes tended to develop breast tumors that do not express hormonal receptors, which are typically associated with poor prognosis.

Unexploited Antineoplastic Effects of Commercially Available Anti-Diabetic Drugs

The development of efficacious antitumor compounds with minimal toxicity is a hot research topic. Numerous cancer cell targeted agents are evaluated daily in laboratories for their antitumorigenicity at the pre-clinical level, but the process of their introduction into the market is costly and time-consuming. More importantly, even if these new antitumor agents manage to gain approval, clinicians have no former experience with them. Accruing evidence supports the idea that several medications already used to treat pathologies other than cancer display pleiotropic effects, exhibiting multi-level anti-cancer activity and chemosensitizing properties. This review aims to present the anticancer properties of marketed drugs (i.e., metformin and pioglitazone) used for the management of diabetes mellitus (DM) type II. Mode of action, pre-clinical in vitro and in vivo or clinical data as well as clinical applicability are discussed here. Given the precious multi-year clinical experience with these non-antineoplastic drugs their repurposing in oncology is a challenging alternative that would aid towards the development of therapeutic schemes with less toxicity than those of conventional chemotherapeutic agents. More importantly, harnessing the antitumor function of these agents would save precious time from bench to bedside to aid the fight in the arena of cancer.

The Interactions of Obesity, Inflammation and Insulin Resistance in Breast Cancer

Obese postmenopausal women have an increased breast cancer risk, the principal mechanism for which is elevated estrogen production by adipose tissue; also, regardless of menstrual status and tumor estrogen dependence, obesity is associated with biologically aggressive breast cancers. Type 2 diabetes has a complex relationship with breast cancer risk and outcome; coexisting obesity may be a major factor, but insulin itself induces adipose aromatase activity and estrogen production and also directly stimulates breast cancer cell growth and invasion. Adipose tissue inflammation occurs frequently in obesity and type 2 diabetes, and proinflammatory cytokines and prostaglandin E2 produced by cyclooxygenase-2 in the associated infiltrating macrophages also induce elevated aromatase expression. In animal models, the same proinflammatory mediators, and the chemokine monocyte chemoattractant protein-1, also stimulate tumor cell proliferation and invasion directly and promote tumor-related angiogenesis. We postulate that chronic adipose tissue inflammation, rather than body mass index-defined obesity per se, is associated with an increased risk of type 2 diabetes and postmenopausal estrogen-dependent breast cancer. Also, notably before the menopause, obesity and type 2 diabetes, or perhaps the associated inflammation, promote estrogen-independent, notably triple-negative, breast cancer development, invasion and metastasis by mechanisms that may involve macrophage-secreted cytokines, adipokines and insulin.

Prognosis of small cell lung cancer patients with diabetes treated with metformin

BACKGROUNDS

It has been reported that metformin has an anticancer impact in various solid tumors, but its role in small cell lung cancer (SCLC) remains unclear. This study aimed to investigate the effect of metformin on survival in diabetic SCLC patients.

METHODS

A total of 79 SCLC patients with diabetes treated in our hospital between 2000 and 2010 were enrolled. The clinicopathological data and survival time were collected and evaluated. Univariate and multivariate analyses were used to investigate the association between metformin use and the survival of SCLC.

RESULTS

Among the 79 diabetic patients, 36 patients took metformin. The median OS and DFS were significantly better in the metformin group compared to non-metformin group (OS 18.0 vs 11.5 months, p < 0.001; DFS 10.8 vs 6.5 months, p < 0.001). Multivariate Cox analysis indicated that metformin use was an independent prognostic factor for long-term outcome (HR = 0.549, 95 % CI 0.198-0.978, p = 0.001).

CONCLUSIONS

The prognosis of SCLC patients with diabetes treated with metformin was improved, which might be considered a potential useful anticancer drug in treating SCLC patients.

Recent prediagnostic aspirin use, lymph node involvement, and 5-year mortality in women with stage I-III breast cancer: a nationwide population-based cohort study

Lymph node-positive breast tumors are more likely to express COX2 than node-negative tumors. In preclinical studies, COX2 inhibition prevents breast tumor spread to lymph nodes. Therefore, we examined the association between recent (1 year) prediagnostic use of aspirin (COX1/COX2 inhibitor), lymph node involvement at breast cancer diagnosis, and breast cancer-specific mortality. Women with stage I-III breast cancer diagnosed from 2001 to 2006 (N = 2,796) were identified from Ireland's National Cancer Registry. These data were linked to prescription refill and mammographic screening databases. Relative risks (RR) were estimated for associations between prediagnostic aspirin use and lymph node-positive status at diagnosis. HRs were estimated for associations between pre- and postdiagnostic aspirin use and 5-year mortality, stratified by lymph node status. Women with prediagnostic aspirin use were statistically significantly less likely to present with a lymph node-positive tumor than nonusers [RR = 0.89; 95% confidence interval (CI), 0.81-0.97], particularly those with larger (Pinteraction = 0.036), progesterone receptor (PR)-negative (Pinteraction < 0.001) or estrogen receptor (ER)-negative (Pinteraction = 0.056) tumors. The magnitude of this association increased with dose (Ptrend < 0.01) and dosing intensity (Ptrend < 0.001) and was similar in women with or without screen-detected tumors (Pinteraction = 0.70). Prediagnostic aspirin use was associated with lower 5-year breast cancer-specific mortality among women with lymph node-negative tumors (HR, 0.55; 95% CI, 0.33-0.92) but not node-positive tumors (HR, 0.91; 95% CI, 0.37-1.22). Tests for effect-modification were, however, not statistically significant (Pinteraction = 0.087). Postdiagnostic aspirin use was not associated with breast cancer-specific mortality (HR, 0.99; 95% CI, 0.68-1.45). Our findings indicate that recent prediagnostic aspirin use is protective against lymph node-positive breast cancer. This is a plausible explanation for reductions in breast cancer mortality reported in observational studies of aspirin use.

The influence of diabetes severity on receipt of guideline-concordant treatment for breast cancer

Diabetes severity may influence breast cancer treatment choices. We examined whether receipt of guideline-concordant breast cancer treatment varied with diabetes severity. Cancer registry data from seven states regarding 6,912 stage I-III breast cancers were supplemented by medical record abstraction and physician verification. We used logistic regression models to examine associations of diabetes severity with guideline-concordant locoregional treatment, adjuvant chemotherapy, and hormonal therapy adjusted for sociodemographics, comorbidity, and tumor characteristics. We defined guideline concordance using National Comprehensive Cancer Network guidelines, and diabetes and comorbidities using the Adult Comorbidity Evaluation-27 index. After adjustment, there was significant interaction of diabetes severity with age for locoregional treatment (p = 0.001), with many diabetic women under age 70 less frequently receiving guideline-concordant treatment than non-diabetic women. Among similarly aged women, guideline concordance was lower for women with mild diabetes in their late fifties through mid-sixties, and with moderate/severe diabetes in their late forties to early sixties. Among women in their mid-seventies to early eighties, moderate/severe diabetes was associated with increased guideline concordance. For adjuvant chemotherapy, moderate/severe diabetes was less frequently associated with guideline concordance than no diabetes [OR 0.58 (95 % CI 0.36-0.94)]. Diabetes was not associated with guideline-concordant hormonal treatment (p = 0.929). Some diabetic women were less likely to receive guideline-concordant treatment for stage I-III breast cancer than non-diabetic women. Diabetes severity was associated with lower guideline concordance for locoregional treatment among middle-aged women, and lower guideline concordance for adjuvant chemotherapy. Differences were not explained by comorbidity and may contribute to potentially worse breast cancer outcomes.

Long-term use of metformin and the molecular subtype in invasive breast carcinoma patients - a retrospective study of clinical and tumor characteristics

BACKGROUND

Metformin may exhibit inhibitory effects on cancer cells by inhibiting mTOR signaling pathway. The aim of our retrospective study was to examine if patients with breast carcinoma (BC) and diabetes mellitus (DM) receiving metformin have a lower stage of carcinoma in comparison to patients not receiving metformin, and if the use of metformin correlates with the molecular subtype of BC.

METHODS

A chart review of 253 patients with invasive BC and DM (128 on metformin and 125 not on metformin) was performed. Control group consisted of 320 consecutive patients with invasive BC without DM. BC subtypes were classified by immunohistochemical surrogates as luminal A (estrogen receptor [ER] + and/or progesterone receptor [PR]+, HER-2-), luminal B (ER + and/or PR+, HER-2+), HER-2 (ER-, PR-, HER-2+), triple-negative/basal (ER-, PR-, HER-2-).

RESULTS

Patients on metformin had a lower proportion of T3 or T4 tumors than patients who were not receiving metformin (16% vs. 26%; p = 0.035). No statistical difference was found between the two study groups in N stage. Patients with DM on metformin, with DM not on metformin and the control group had different molecular subtypes of BC (p = 0.01): the luminal A subtype was found in 78%, 83% and 71%, the luminal B in 12.6%, 9% and 11%, HER-2 in 0.8%, 1.6% and 8%, and the triple-negative/basal-like subtype in 8.6%, 6.4% and 10%, respectively.

CONCLUSION

Our data indicate that long-term use of metformin use correlates with molecular subtype of BC in diabetics on metformin in comparison to diabetics not on metformin and patients without DM. However, most likely, different distribution of the molecular subtypes of BC in these three groups of patients was caused by other risk factors for breast carcinoma, such as age of patients or obesity.

Diabetes and cancer: two diseases with obesity as a common risk factor

There is a growing body of evidence to support a connection between diabetes (predominantly type 2), obesity and cancer. Multiple meta-analyses of epidemiological data show that people with diabetes are at increased risk of developing many different types of cancers, along with an increased risk of cancer mortality. Several pathophysiological mechanisms for this relationship have been postulated, including insulin resistance and hyperinsulinaemia, enhanced inflammatory processes, dysregulation of sex hormone production and hyperglycaemia. In addition to these potential mechanisms, a number of common risk factors, including obesity, may be behind the association between diabetes and cancer. Indeed, obesity is associated with an increased risk of cancer and diabetes. Abdominal adiposity has been shown to play a role in creating a systemic pro-inflammatory environment, which could result in the development of both diabetes and cancer. Here, we examine the relationship between diabetes, obesity and cancer, and investigate the potential underlying causes of increased cancer risk in individuals with diabetes. Current treatment recommendations for reducing the overall disease burden are also explored and possible areas for future research are considered.

Insulin glargine versus other types of basal insulin-clinical and tumor characteristics in patients with breast carcinoma

Background

Recent epidemiological studies have suggested that some insulin analogues could be associated with an increased risk of cancer. The aim of this retrospective study was to examine whether patients with diabetes mellitus (DM) using insulin glargine have a higher tumor stage of breast carcinoma in comparison to patients using other types of insulin.

Methods

We performed a chart review of 79 surgically treated breast carcinoma patients (mean age of 66.5 years; range 38-86 years) who were on insulin. Insulin glargine was used in 13 patients, while the other 66 patients were on other types of insulin. Clinical and histopathology characteristics of patients on glargine versus other types of insulin were compared using a chi-square test and non-parametric statistical analysis.

Results

DM type 1 and DM type 2 was present in 14 and 65 patients, respectively. The mean tumor size was 2.98 cm. The TNM tumor stage at diagnosis was not higher among patients on glargine compared to patients on other types of insulin (T1/T2 85% vs. 68%, T3/T4 15% vs. 32%, p = 0.32; N1 54% vs. 58%, p = 0.80; M1 8% vs. 6%, respectively). No significant differences between both study groups (glargine vs. other types of insulin) were found in the ages of the patients, their BMI, tumor histology, grade, number of metastatic lymph nodes, hormone receptors or HER-2 status.

Conclusion

We could not show that patients with DM using insulin glargine have a higher tumor stage of breast carcinoma in comparison to those using other types of insulin.

Diabetes in women: a life-course approach

The increasing prevalence of diabetes in combination with an aging population and increasing female longevity means that it is important to understand the effects of diabetes on women's health. Both type 1 and type 2 diabetes influence health outcomes throughout the life-course. This review article provides a summary of sex differences in diabetes epidemiology and covers specific aspects of the life-course in women including: the menarche, pregnancy and the menopause. It also discusses the associations with other conditions: cardiovascular disease, osteoporosis and cancer.

Diabetes mellitus impacts risk of macrovascular invasion in patients undergoing transplantation for hepatocellular carcinoma

Background

Diabetes mellitus (DM) is identified as a negative prognostic indicator in hepatocellular carcinoma (HCC), though the basis for this is unknown.

Methods

This is a retrospective analysis of a prospectively collected database of 191 HCC patients treated at the University of Rochester Medical Center (URMC) with orthotopic liver transplantation between 1998–2008. Clinical characteristics were compared between patients with and without DM prior to liver transplantation and logistic regression analyses were conducted to assess the effect of DM on clinical outcomes including vascular invasion.

Results

Eighty-four of 191 (44%) transplanted patients had DM at time of transplantation. An association of DM with invasive disease was found among transplanted HCC patients where histologically confirmed macrovascular invasion was found in 20.2% (17/84) of diabetics compared to 9.3% of non-diabetics (10/107) (p=0.032). This difference also remained significant when adjusting for tumor size, number of nodules, age, obesity and etiologic risk factors in multivariate logistic regression analysis (OR=3.2, p=0.025).

Conclusions

DM is associated with macrovascular invasion among a cohort of transplanted HCC patients.

High glucose and insulin differentially modulates proliferation in MCF-7 and MDA-MB-231 cells

Various preclinical and clinical studies have linked diabetes and breast cancer, but little is known regarding the molecular mechanism involved. This study aimed to investigate the effect of high glucose and insulin in breast cancer cells (MCF-7: non-invasive, hormone dependent, and MDA-MB-231: invasive, hormone independent). In contrast to MCF-7 cells, high glucose augmented proliferation of MDA-MB-231 cells as observed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and bromodeoxyuridine assays. The high-glucose condition led to increased expression of cyclin D1, de-phosphorylation of p38, and increased phosphorylation of ERK in MDA-MB-231 cells but not in MCF-7 cells. Interestingly, we observed increased phosphorylation of GSK-3β, NF-κB, and ERα only in MCF-7 cells, highlighting their role as potential targets in prevention of progression of breast cancer under a high-glucose and insulin condition. Furthermore, insulin treatment under a high-glucose condition resulted in increased histone H3 phosphorylation and de-acetylation only in MDA-MB-231 cells. Taken together, we provide the first evidence that high glucose and insulin promotes proliferation of MDA-MB-231 cells by differential alteration of GSK-3β, NF-κB, and ERα expression and histone H3 modifications, which may directly or indirectly modulate the expression of genes involved in its proliferation.

Associations between TCF7L2 polymorphisms and risk of breast cancer among Hispanic and non-Hispanic white women: the Breast Cancer Health Disparities Study

The transcription factor 7-like 2 (TCF7L2) gene is part of the Wnt/β-catenin signaling pathway and plays a critical role in cell development and growth regulation. TCF7L2 variants rs12255372 and rs7903146 have been associated with risk of Type 2 diabetes. Few epidemiological studies have examined the association between TCF7L2 and breast cancer risk. We investigated the associations between 25 TCF7L2 single nucleotide polymorphisms (SNPs) and breast cancer in Hispanic and non-Hispanic white (NHW) women from the 4-Corner's Breast Cancer Study, the San Francisco Bay Area Breast Cancer Study, and the Mexico Breast Cancer Study. A total of 4,703 Hispanic (2,093 cases, 2,610 controls) and 3,031 NHW (1,431 cases, 1,600 controls) women were included. Odds ratios (OR) and 95 % confidence intervals (CI) were calculated using logistic regression to estimate the association between the TCF7L2 SNPs and breast cancer risk. We also examined effect modification by self-reported ethnicity, genetic admixture, and diabetes history. After adjusting for multiple comparisons, four TCF7L2 SNPs were significantly associated with breast cancer overall: rs7903146 (OR(TT) 1.24; 95 % CI 1.03-1.49), rs3750805 (OR(AT/TT) 1.15; 95 % CI 1.03-1.28), rs7900150 (OR(AA) 1.23; 95 % 1.07-1.42), and rs1225404 (OR(CC) 0.82; 95 % 0.70-0.94). Among women with a history of diabetes, the TT genotype of rs3750804 increased breast cancer risk (OR, 2.46; 95 % CI 1.28-4.73). However, there was no association among women without a diabetes history (OR, 1.06; 95 % CI 0.85-1.32). We did not find significant interactions by ethnicity or by genetic admixture. Findings support an association between TCF7L2 and breast cancer and history of diabetes modifies this association for specific variants.

Diabetes mellitus is associated with the presence of metastatic spread at disease presentation in hepatocellular carcinoma

PURPOSE

Diabetes mellitus (DM) is identified as a negative prognostic indicator in hepatocellular carcinoma (HCC).

METHODS

A retrospective review of HCC patients was conducted to assess the effect of DM on clinical variables.

RESULTS

Ninety-seven of 265 (34%) patients had DM at the time of diagnosis. Distant metastasis was found in 33% (30/91) of patients with DM compared with only 9.7% (17/174) of those without DM (OR: 4.5, 95% CI: 2.3-8.8, p < .0001). This difference remained significant when adjusting for other clinical variables (OR: 10.0, 95% CI: 3.9-25.7, p < .0001).

CONCLUSIONS

DM is associated with the presence of metastatic disease among a single institution cohort of HCC patients.

Diabetes and pancreatic cancer

Type 2 diabetes mellitus is likely the third modifiable risk factor for pancreatic cancer after cigarette smoking and obesity. Epidemiological investigations have found that long-term type 2 diabetes mellitus is associated with a 1.5-fold to 2.0-fold increase in the risk of pancreatic cancer. A causal relationship between diabetes and pancreatic cancer is also supported by findings from prediagnostic evaluations of glucose and insulin levels in prospective studies. Insulin resistance and associated hyperglycemia, hyperinsulinemia, and inflammation have been suggested to be the underlying mechanisms contributing to development of diabetes-associated pancreatic cancer. Signaling pathways that regulate the metabolic process also play important roles in cell proliferation and tumor growth. Use of the antidiabetic drug metformin has been associated with reduced risk of pancreatic cancer in diabetics and recognized as an antitumor agent with the potential to prevent and treat this cancer. On the other hand, new-onset diabetes may indicate subclinical pancreatic cancer, and patients with new-onset diabetes may constitute a population in whom pancreatic cancer can be detected early. Biomarkers that help define high-risk individuals for clinical screening for pancreatic cancer are urgently needed. Why pancreatic cancer causes diabetes and how diabetes affects the clinical outcome of pancreatic cancer have yet to be fully determined. Improved understanding of the pathological mechanisms shared by diabetes and pancreatic cancer would be the key to the development of novel preventive and therapeutic strategies for this cancer.

Effect of metformin on survival outcomes in diabetic patients with triple receptor-negative breast cancer

BACKGROUND

Recent observational studies have shown that metformin use in diabetic patients decreases both cancer incidence and mortality. Metformin use is also independently predictive of pathologic complete response. In the current study, the authors explored the association between metformin use and survival outcomes in patients with triple receptor-negative breast cancer (TNBC) who were receiving adjuvant chemotherapy.

METHODS

The Breast Cancer Management System database of The University of Texas MD Anderson Cancer Center identified 1448 women who received adjuvant chemotherapy for TNBC between 1995 and 2007. Patients were categorized by diabetes status and metformin use. The Kaplan-Meier product-limit method was used to calculate distant metastasis-free survival (DMFS), recurrence-free survival (RFS), and overall survival (OS). Cox proportional hazards models were fit to determine the association between metformin use and survival outcomes.

RESULTS

The study cohort was comprised of 63 diabetic patients receiving treatment with metformin, 67 diabetic patients not receiving metformin, and 1318 nondiabetic patients. Patients in the diabetic groups tended to be older (P = .005); more diabetic patients were postmenopausal (P = .0007), black (P = .0001), and obese (P < .0001). At a median follow-up of 62 months, there were no significant differences with regard to 5-year DMFS (P = .23), RFS (P = .38), and OS (P = .58) between the 3 groups. Compared with the metformin group, patients who did not receive metformin (hazard ratio [HR], 1.63; 95% confidence interval [95% CI], 0.87-3.06 [P = .13]) and nondiabetic patients (HR, 1.62; 95% CI, 0.97-2.71 [P = .06]) tended to have a higher risk of distant metastases.

CONCLUSIONS

The findings of the current study suggest that metformin use during adjuvant chemotherapy does not significantly impact survival outcomes in diabetic patients with TNBC.

The peptide-hormone glucagon-like peptide-1 activates cAMP and inhibits growth of breast cancer cells

The incretin hormone glucagon-like peptide (GLP)-1 is secreted from intestinal L cells in response to food intake, and promotes insulin secretion and pancreatic β-cell proliferation. Reduced GLP-1 levels are observed in obesity and type 2 diabetes mellitus (T2DM) and are associated with reduced insulin secretion and increased insulin resistance. GLP-1 mediates its activities through activation of a G-protein coupled receptor, which is expressed in the pancreas, as well as other tissues. Long-acting GLP-1 receptor (GLP-1R) agonists, such as exendin-4, are currently approved for the treatment of T2DM. As obesity and T2DM are associated with increased risk of breast cancer, we aimed to explore the effects of GLP-1 and exendin-4, on breast cancer cells. Treatment with GLP-1 or exendin-4 reduced viability and enhanced apoptosis of breast cancer cells but did not affect viability of nontumorigenic cells. Moreover, exendin-4 attenuated tumor formation by breast cancer cells in athymic mice. Treatment with either GLP-1 or exendin-4 elevated cAMP levels, activated the down-stream target CREB, and enhanced CRE promoter transcription, in breast cancer cells. Moreover, inhibition of exendin-4-induced adenylate cyclase activation restored cell viability, thus suggesting cAMP as a principle mediator of exendin-4 anti-tumorigenic activity. While the pancreatic form of the GLP-1R could not be detected in breast cancer cells, several lines of evidence indicated the existence of an alternative GLP-1R in mammary cells. Thus, internalization of GLP-1 into MCF-7 cells was evidenced, infection of MCF-7 cells with the pancreatic receptor enhanced proliferation, and treatment with exendin-(9-39), a GLP-1R antagonist, further increased cAMP levels. Our studies indicate the incretin hormone GLP-1 as a potent inducer of cAMP and an inhibitor of breast cancer cell proliferation. Reduced GLP-1 levels may, therefore, serve as a novel link between obesity, diabetes mellitus, and breast cancer.

Klotho is a novel biomarker for good survival in resected large cell neuroendocrine carcinoma of the lung

BACKGROUND

In terms of prognosis, large cell neuroendocrine carcinoma (LCNEC) differs distinctively from other non-small cell lung cancers, with the prognosis of LCNEC being poor, even for early-stage disease. Improvements in survival require a biomarker capable of defining a subset of patients destined to do poorly so that these patients can be targeted for additional therapies, including chemotherapy. In this study, we focused on the Klotho gene, which is an anti-aging gene known to be a potential tumor suppressor. We investigated whether the immunohistochemical expression of Klotho can predict survival patients with resected LCNEC.

METHODS

The histological characteristics of patients receiving an initial diagnosis of LCNEC (n=30) at Tokyo Medical University Hospital were retrospectively reviewed, and multiple variables including stage, lymphangioinvasion, lymph node status and the expression of Klotho as identified using an immunohistochemical analysis, were assessed.

RESULTS

Immunostaining for Klotho was mostly cytoplasmic, and Klotho expression was seen in 10 patients (33.3%) but not in 20 patients (66.7%). The expression of Klotho was significantly associated with a good outcome of resected patients with LCNEC and Klotho(-) was associated with increased LCNEC risk by multivariate analysis (hazard ratio 4.92, 95% confidence interval 1.04-23.24, p=0.044). Neither lymph node status nor lymphangioinvasion were significantly associated with a poor survival. However, among patients without lymph node metastasis or angioinvasion, the survival benefit of Klotho expression in the primary tumor was significantly higher, compared with that of patients without Klotho expression.

CONCLUSION

Klotho staining provides a new biomarker for a good outcome in patients with LCNEC, especially among patients without lymph node metastasis or lymphangioinvasion.

More favorable progesterone receptor phenotype of breast cancer in diabetics treated with metformin

The coexistence of type 2 diabetes with breast cancer may result in poorer cancer-related survival due to a number of mediating factors including an alteration of tumor tissue hormonal sensitivity. Previous studies have shown that receptor status of breast tumors in diabetics may be changed; however, the mode of therapy for diabetes was usually ignored. This work presents the results of an analysis of the receptor status of breast carcinomas in 90 postmenopausal women suffering with diabetes mellitus type 2 who had been cured, for not less that 1 year prior to surgery, with different modes of antidiabetic therapy, including a dietary treatment only, sulfonylurea preparations, insulin therapy, and metformin as a monotherapy or in combination with sulfonylurea derivatives. No differences in estrogen receptors occurrence in tumor tissue were found in different treatment groups. The frequency of progesterone receptor-positive mammary carcinomas in women who were treated with metformin, irrespective of whether it was combined with sulfonylurea preparations, was significantly higher than in the sulfonylurea only group (P=0.043) and in the combined group of patients treated with either sulfonylurea or insulin (P=0.041). The exclusion of the patients who received neoadjuvant chemotherapy (24 persons) did not significantly affect the above results. The data may be used as an explanation of the distinctions in cancer characteristics and course between diabetic patients treated with either metformin or sulfonylurea derivatives and insulin.

Biomarkers of the metabolic syndrome and breast cancer prognosis

In spite of its public health importance, our understanding of the mechanisms of breast carcinogenesis and progress is still evolving. The metabolic syndrome (MS) is a constellation of biochemical abnormalities including visceral adiposity, hyperglycemia, hyperinsulinemia, dyslipidemia and high blood pressure. The components of the MS have all been related to late-stage disease and even to a poor prognosis of breast cancer through multiple interacting mechanisms. In this review, we aim to present a summary of recent advances in the understanding of the contribution of the MS to breast cancer with the emphasis on the role of biomarkers of the MS in the prognosis of breast cancer.

Obesity and angiolymphatic invasion in primary breast cancer

BACKGROUND

Obesity is associated with poorer breast cancer-specific survival. The purpose of this study was to investigate the relationships between obesity and the presence of angiolymphatic invasion as well as other features of invasive breast cancer, including stage at presentation, estrogen receptor (ER) status, triple-negative phenotype, and tumor grade.

METHODS

Detailed clinical and pathologic data were abstracted from the medical records of all 1,312 patients with stage I-III primary breast cancer who had breast surgery at the University of Michigan Comprehensive Cancer Center between January 1, 2000 and December 31, 2006. Bivariate and multivariate analyses were conducted to investigate the relationships between body mass index and tumor biologic features, controlling for menopausal status, diabetes and hypertension, hormone replacement therapy before diagnosis, race, and ethnicity.

RESULTS

In multivariate analyses, severe obesity was independently associated with the presence of angiolymphatic invasion [odds ratio (OR) 1.80, 95% confidence interval (CI) 1.08-2.99, joint test of significance, P = 0.03]. Severe obesity was associated with lower likelihood of triple-negative breast cancer (OR 0.39, 95% CI 0.16-0.96). Among premenopausal women with diabetes, ER-negative (OR 5.22, 95% CI 1.12-24.29) and triple-negative (OR 14.8, 95% CI 1.92-113.91) disease was significantly more common.

DISCUSSION

In this large sample of invasive breast cancers, obesity was independently associated with the presence of angiolymphatic invasion. Higher rates of angiolymphatic invasion among obese women may account in part for poorer outcomes among obese women with breast cancer.

Klotho and aging

The klotho gene encodes a single-pass transmembrane protein that forms a complex with multiple fibroblast growth factor (FGF) receptors and functions as an obligatory co-receptor for FGF23, a bone-derived hormone that induces negative phosphate balance. Defects in either Klotho or Fgf23 gene expression cause not only phosphate retention but also a premature-aging syndrome in mice, unveiling a potential link between phosphate metabolism and aging. In addition, the extracellular domain of Klotho protein is clipped on the cell surface and secreted into blood stream, potentially functioning as an endocrine factor. The secreted Klotho protein has a putative sialidase activity that modifies glycans on the cell surface, which may explain the ability of secreted Klotho protein to regulate activity of multiple ion channels and growth factors including insulin, IGF-1, and Wnt. Secreted Klotho protein also protects cells and tissues from oxidative stress through a mechanism yet to be identified. Thus, the transmembrane and secreted forms of Klotho protein have distinct functions, which may collectively affect aging processes in mammals.

Diabetes mellitus and outcomes of colorectal cancer

BACKGROUND

Patients with diabetes mellitus have an increased risk of colorectal cancer. However, there is limited information on the outcome for diabetic patients diagnosed with this type of cancer.

METHODS

The health records of all 1 194 patients treated for colorectal adenocarcinoma at Levanger Hospital from 1980-2004 were reviewed. Diabetes status and prognostic factors were registered. Primary endpoints were cancer specific survival and overall survival.

RESULTS

There were no significant differences between diabetic patients and non-diabetic patients concerning stage, grade, treatment, infective or non-infective postoperative complications, hospital stay, or 30 days mortality after laparotomy. After a curative resection, the estimated 5-year cancer specific survival in 97 diabetic patients was 73% (95% CI 60-87) and 79% (95% CI 75-82) in 1097 non-diabetic patients (not significant). The estimated overall 5-year survival in patients treated with curative intent was 46% (95% CI 33-59) in diabetic patients and 65% (95% CI 62-69) in non-diabetic patients (p<0.001). The diabetic patients were significantly older and more frequently had cardiac diseases.

CONCLUSION

Diabetes mellitus did not affect the short-term survival or the cancer specific survival. A shorter overall survival was associated with cardiac diseases and higher age.

Prevalence and trends of receipt of cancer screenings among US women with diagnosed diabetes

BACKGROUND

Diabetes increases the risk of breast and colorectal cancers and has an undetermined relationship to cervical cancer. Improved screenings for these cancers are effective in reducing cancer mortality.

OBJECTIVES

To examine the prevalence of receiving recommended screenings for these cancers and to assess the trends in the screening rates over time among US women with diagnosed diabetes in comparison with women without diabetes.

DESIGN

Cross-sectional.

PARTICIPANTS

A total of 63,650 to 182,168 adult women participated in the 1996-2006 (biennially) Behavioral Risk Factor Surveillance System.

METHODS

The prevalence of receiving cancer screenings was age-standardized to the 2000 US population. The adjusted prevalence and adjusted odds ratios (AORs) with 95% confidence intervals (CIs) were estimated using logistic regression analyses. The linear trends in the screening rates were tested using orthogonal polynomial contrasts.

RESULTS

In 2006, women with diabetes had a lower adjusted prevalence (74% versus 79%, P < 0.05) and the AOR (0.73, 95% CI: 0.66-0.81) for receiving cervical cancer screenings, but had a higher adjusted prevalence (63% versus 60%, P < 0.05) and the AOR (1.14, 95% CI: 1.04-1.24) for receiving colorectal cancer screenings compared to those without. In both women with diabetes and those without, the screening rate for colorectal cancer increased linearly during 2002-2006, whereas the screening rates for breast and cervical cancers changed little during 1996-2006.

CONCLUSION

Women with diabetes were equally likely to be screened for breast cancer, less likely to be screened for cervical cancer, but more likely to be screened for colorectal cancer compared to those without. Overall, the screening rates in both groups remain below the recommended levels.

Secular trend for mortality from breast cancer and the association between diabetes and breast cancer in Taiwan between 1995 and 2006

AIMS/HYPOTHESIS

Studies have identified an association between diabetes and breast cancer in postmenopausal women in Western countries. Such an association needs to be confirmed in an Asian population. The aim of this study was to evaluate the secular trend for breast cancer mortality in Taiwanese women in the general population and the mortality rate ratios between diabetic patients and the general population.

METHODS

Age-specific mortality rates for the general population, categorised into groups aged 25-54, 55-64, 65-74 and > or =75 years, were calculated for the years between 1995 and 2006 (inclusive) from vital statistics published by the Taiwanese government. Linear regression was used to test the trends. A total of 131,573 diabetic women aged > or =25 years from a national cohort recruited between 1995 and 1998 (inclusive) were followed prospectively for vital status, determined from the National Register of Deaths. Mortality rates and mortality rate ratios (mortality rate in diabetic women vs the average and highest mortality rates for the general population) were calculated.

RESULTS

A total of 14,230 women aged > or =25 years in the general population died of breast cancer between 1995 and 2006. A trend for an increase in the annual rate was observed for all age groups. A total of 482 diabetic women died of breast cancer, with a crude mortality rate of 45.7 per 100,000 person-years. Compared with the general population the relative risk of mortality for those with diabetes ranged from 1.37 (for the group aged 55-64 years) to 2.43 (for the group aged 25-54 years).

CONCLUSIONS/INTERPRETATION

We identified a secular trend of an increase in the rate of breast cancer mortality in the Taiwanese general population. Our data suggest a higher risk of breast cancer mortality in diabetic patients in all age groups.

Klotho: a tumor suppressor and a modulator of the IGF-1 and FGF pathways in human breast cancer

Klotho is an anti-aging gene, which has been shown to inhibit the insulin and insulin-like growth factor 1 (IGF-1) pathways in mice hepatocytes and myocytes. As IGF-1 and insulin regulate proliferation, survival and metastasis of breast cancer, we studied klotho expression and activities in human breast cancer. Immunohistochemistry analysis of klotho expression in breast tissue arrays revealed high klotho expression in normal breast samples, but very low expression in breast cancer. In cancer samples, high klotho expression was associated with smaller tumor size and reduced KI67 staining. Forced expression of klotho reduced proliferation of MCF-7 and MDA-MB-231 breast cancer cells, whereas klotho silencing in MCF-7 cells, which normally express klotho, enhanced proliferation. Moreover, forced expression of klotho in these cells, or treatment with soluble klotho, inhibited the activation of IGF-1 and insulin pathways, and induced upregulation of the transcription factor CCAAT/enhancer-binding protein beta, a breast cancer growth inhibitor that is negatively regulated by the IGF-1-AKT axis. Co-immunoprecipitation revealed an interaction between klotho and the IGF-1 receptor. Klotho is also a known modulator of the fibroblast growth factor (FGF) pathway, a pathway that inhibits proliferation of breast cancer cells. Studies in breast cancer cells revealed increased activation of the FGF pathway by basic FGF following klotho overexpression. Klotho did not affect activation of the epidermal growth factor pathway in breast cancer cells. These data suggest klotho as a potential tumor suppressor and identify it as an inhibitor of the IGF-1 pathway and activator of the FGF pathway in human breast cancer.

Study Protocol: insulin and its role in cancer

BACKGROUND

Studies have shown that metabolic syndrome and its consequent biochemical derangements in the various phases of diabetes may contribute to carcinogenesis. A part of this carcinogenic effect could be attributed to hyperinsulinism. High levels of insulin decrease the production of IGF-1 binding proteins and hence increase levels of free IGF-1. It is well established that bioactivity of free insulin growth factor 1 (IGF-1) increases tumor turnover rate. The objective is to investigate the role of insulin resistance/sensitivity in carcinogenesis by studying the relation between insulin resistance/sensitivity and IGF-1 levels in cancer patients. We postulate that hyperinsulinaemia which prevails during initial phases of insulin resistance (condition prior to overt diabetes) increases bioactivity of free IGF-1, which may contribute to process of carcinogenesis.

METHODS/DESIGN

Based on our pilot study results and power analysis of the same, we have designed a two group case-control study. 800 proven untreated cancer patients (solid epithelial cell tumors) under age of 50 shall be recruited with 200 healthy subjects serving as controls. Insulin resistance/sensitivity and free IGF-1 levels shall be determined in all subjects. Association between the two parameters shall be tested using suitable statistical methods.

DISCUSSION

Well controlled studies in humans are essential to study the link between insulin resistance, hyperinsulinaemia, IGF-1 and carcinogenesis. This study could provide insights to the role of insulin, insulin resistance, IGF-1 in carcinogenesis although a precise role and the extent of influence cannot be determined. In future, cancer prevention and treatment strategies could revolve around insulin and insulin resistance.

Diabetes mellitus and risk of breast cancer: A meta-analysis

Diabetes mellitus has been associated with an increased risk of several types of cancers, but its relationship with breast cancer remains unclear. We conducted a meta-analysis of case-control and cohort studies to assess the evidence regarding the association between diabetes and risk of breast cancer. Studies were identified by searching MEDLINE (1966-February 2007) and the references of retrieved articles. We identified 20 studies (5 case-control and 15 cohort studies) that reported relative risk (RR) estimates (odds ratio, rate ratio/hazard ratio, or standardized incidence ratio) with 95% confidence intervals (CIs) for the relation between diabetes (largely Type II diabetes) and breast cancer incidence. Summary RRs were calculated using a random-effects model. Analysis of all 20 studies showed that women with (versus without) diabetes had a statistically significant 20% increased risk of breast cancer (RR, 1.20; 95% CI, 1.12-1.28). The summary estimates were similar for case-control studies (RR, 1.18; 95% CI, 1.05-1.32) and cohort studies (RR, 1.20; 95% CI, 1.11-1.30). Meta-analysis of 5 cohort studies on diabetes and mortality from breast cancer yielded a summary RR of 1.24 (95% CI, 0.95-1.62) for women with (versus without) diabetes. Findings from this meta-analysis indicate that diabetes is associated with an increased risk of breast cancer.