Medical comorbidities predict mortality in women with a history of early stage breast cancer

Diet and breast cancer: understanding risks and benefits

BACKGROUND

Breast cancer is the most commonly diagnosed cancer among women in the United States. Extensive research has been completed to evaluate the relationship between dietary factors and breast cancer risk and survival after breast cancer; however, a summary report with clinical inference is needed. Materials and

METHODS

This review summarizes the current epidemiological and clinical trial evidence relating diet to breast cancer incidence, recurrence, survival, and mortality. The review includes emerging epidemiological studies that assess risk within breast cancer subtypes as well as a summary of previous and ongoing dietary intervention trials designed to modify breast cancer risk.

RESULTS

The available literature suggests that both low-fat and high-fiber diets may be weakly protective against breast cancer, whereas total energy intake and alcohol appear to be positively associated. Fiber may be weakly protective possibly through modulation of estrogen, whereas fruit and vegetable intake is not clearly associated with risk. Obesity is a risk factor for postmenopausal disease, and adult weight gain should be avoided to reduce risk. In survivors, diet has the greatest potential influence on overall mortality rather than breast cancer-specific events.

CONCLUSION

Diet is modestly associated with breast cancer risk; associations appear more pronounced for postmenopausal disease, and healthy choices after diagnosis and treatment likely support longevity more so than reduced risk for recurrent disease.

Associations of soluble fiber, whole fruits/vegetables, and juice with plasma Beta-carotene concentrations in a free-living population of breast cancer survivors

OBJECTIVE

Soluble fiber and the physical state of fruits/vegetables affect plasma ß-carotene concentrations; however, most of this research was conducted in laboratory-based settings. These analyses investigated the relationship between soluble fiber and juiced versus whole fruits/vegetables to plasma ß-carotene concentrations in a free-living population.

METHOD

This cross-sectional analysis used 12-month follow-up data from the Women's Healthy Eating & Living Study (1995-2006), a study to improve diet in breast cancer survivors in the Western United States. The dietary nutrients considered in this analysis included intake of soluble fiber (g), ß-carotene from fruit/vegetable juice (mg), and ß-carotene from whole fruits/vegetables (mg). A linear regression model was used to assess the relationship of the variables to plasma ß-carotene concentrations.

RESULTS

Out of 3,088 women enrolled in the Women's Healthy Eating & Living Study, 2,397 women had complete data (mean age = 54). The final model accounted for approximately 49% of the explained variance in plasma ß-carotene concentrations. Fruit/vegetable juice had the largest positive relation to plasma ß-carotene concentrations (standardized parameter estimate = 0.23, p < 0.01), followed by whole fruits/vegetables (standardized parameter estimate = 0.09, p < 0.01).

CONCLUSION

Soluble fiber may inhibit ß-carotene absorption; therefore, consumption of juice may increase plasma ß-carotene concentrations more than whole fruits/vegetables in free-living populations.

Body mass index, tumor characteristics, and prognosis following diagnosis of early-stage breast cancer in a mammographically screened population

PURPOSE

Many studies suggest increased body mass index (BMI) is associated with worse breast cancer outcomes, but few account for variability in screening, access to treatment, and tumor differences. We examined the association between BMI and risk of breast cancer recurrence, breast cancer-specific mortality, and all-cause mortality, and evaluated whether tumor characteristics differ by BMI among a mammographically screened population with access to treatment.

METHODS

Using a retrospective cohort study design, we followed 485 women aged ≥40 years diagnosed with stage I/II breast cancer within 24 months of a screening mammogram occurring between 1988 and 1993 for 10-year outcomes. BMI before diagnosis was categorized as normal (<25 kg/m(2)), overweight (25-29.9 kg/m(2)), and obese (≥30 kg/m(2)). Tumor marker expression was assessed via immunohistochemistry using tissue collected before adjuvant treatment. Medical records were abstracted to identify treatment, recurrence, and mortality. We used Cox proportional hazards to separately model the hazard ratios (HR) of our three outcomes by BMI while adjusting for age, stage, and tamoxifen use.

RESULTS

Relative to normal-weight women, obese women experienced increased risk of recurrence (HR 2.43; 95 % CI 1.34-4.41) and breast cancer death (HR 2.41; 95 % CI 1.00-5.81) within 10 years of diagnosis. There was no association between BMI and all-cause mortality. Obese women had significantly faster growing tumors, as measured by Ki-67.

CONCLUSIONS

Our findings add to the growing evidence that obesity may contribute to poorer breast cancer outcomes, and also suggest that increased tumor proliferation among obese women is a pathway that explains part of their excess risk of adverse outcomes.

Obesity, type 2 diabetes, and cancer: the insulin and IGF connection

Epidemiological studies suggest a positive association between obesity and type 2 diabetes mellitus (T2D) with the risk of cancer and cancer-related mortality. Insulin resistance, hyperinsulinemia, increased levels of IGF, elevated levels of steroid and peptide hormones, and inflammatory markers appear to play a role in the connection between these different diseases. Medications, such as metformin and exogenous insulin, used to treat T2D may affect the risk of cancer and cancer-related mortality. Newer therapies targeting the insulin and IGF1 systems are being developed for use in cancer therapy.

Diabetes, metformin, and breast cancer in postmenopausal women

PURPOSE

Emerging evidence suggests that metformin may reduce breast cancer incidence, but reports are mixed and few provide information on tumor characteristics. Therefore, we assessed associations among diabetes, metformin use, and breast cancer in postmenopausal women participating in Women's Health Initiative clinical trials.

PATIENTS AND METHODS

In all, 68,019 postmenopausal women, including 3,401 with diabetes at study entry, were observed over a mean of 11.8 years with 3,273 invasive breast cancers diagnosed. Diabetes incidence status was collected throughout follow-up, with medication information collected at baseline and years 1, 3, 6, and 9. Breast cancers were confirmed by review of central medical records and pathology reports. Cox proportional hazards regression, adjusted for breast cancer risk factors, compared breast cancer incidence in women with diabetes who were metformin users or nonusers with breast cancer incidence in women without diabetes.

RESULTS

Compared with that in women without diabetes, breast cancer incidence in women with diabetes differed by diabetes medication type (P = .04). Women with diabetes receiving medications other than metformin had a slightly higher incidence of breast cancer (hazard ratio [HR], 1.16; 95% CI, 0.93 to 1.45), and women with diabetes who were given metformin had lower breast cancer incidence (HR, 0.75; 95% CI, 0.57 to 0.99). The association was observed for cancers positive for both estrogen receptor and progesterone receptor and those that were negative for human epidermal growth factor receptor 2.

CONCLUSION

Metformin use in postmenopausal women with diabetes was associated with lower incidence of invasive breast cancer. These results can inform future studies evaluating metformin use in breast cancer management and prevention.

A review of cancer in U.S. Hispanic populations

There are compelling reasons to conduct studies of cancer in Hispanics, the fastest growing major demographic group in the United States (from 15% to 30% of the U.S. population by 2050). The genetically admixed Hispanic population coupled with secular trends in environmental exposures and lifestyle/behavioral practices that are associated with immigration and acculturation offer opportunities for elucidating the effects of genetics, environment, and lifestyle on cancer risk and identifying novel risk factors. For example, traditional breast cancer risk factors explain less of the breast cancer risk in Hispanics than in non-Hispanic whites (NHW), and there is a substantially greater proportion of never-smokers with lung cancer in Hispanics than in NHW. Hispanics have higher incidence rates for cancers of the cervix, stomach, liver, and gall bladder than NHW. With respect to these cancers, there are intriguing patterns that warrant study (e.g., depending on country of origin, the five-fold difference in gastric cancer rates for Hispanic men but not Hispanic women). Also, despite a substantially higher incidence rate and increasing secular trend for liver cancer in Hispanics, there have been no studies of Hispanics reported to date. We review the literature and discuss study design options and features that should be considered in future studies.

Prognostic impact of comorbidity among long-term breast cancer survivors: results from the LACE study

BACKGROUND

Little is known about the long-term impact of comorbidity among women with breast cancer.

METHODS

We studied a prospective cohort of 2,272 women with breast cancer, who were recruited following initial breast cancer treatment. Associations of the Charlson comorbidity index (CCI) and hypertension with survival were evaluated in delayed entry Cox proportional hazards models.

RESULTS

During a median follow-up of nine years, higher CCI scores were independently associated with an increased risk of death from all causes [HR, 1.32; 95% confidence interval (CI), 1.13-1.54] and from nonbreast cancer causes (HR, 1.55; 95% CI, 1.19-2.02), but not from breast cancer (HR, 1.14; 95% CI, 0.93-1.41). Hypertension was independently associated with an increased risk of death from all causes (HR, 1.55; 95% CI, 1.20-1.99), from nonbreast cancer causes (HR, 1.67; 95% CI, 1.10-2.54), and from breast cancer (HR, 1.47; 95% CI, 1.03-2.09), but these associations were no longer significant after adjustment for antihypertensive medication. The relationship between the CCI and overall survival was the strongest among women with stage I disease (stage I, HR, 1.65; 95% CI, 1.26-2.16 vs. stage III, HR, 0.53; 95% CI, 0.23-1.25).

CONCLUSION

The CCI was independently associated with lower overall and nonbreast cancer survival, but not with breast cancer-specific survival.

IMPACT

Comorbidity may play an important role in breast cancer outcomes.

The impact of diabetes mellitus on prognosis of early breast cancer in Asia

BACKGROUND

Diabetes mellitus (DM) has been implicated in influencing the survival duration of patients with breast cancer. However, less is known about the impact of DM and other comorbidities on the breast cancer-specific survival (BCS) and overall survival (OS) outcomes of Asian patients with early-stage breast cancer.

PATIENTS AND METHODS

The characteristics of female patients with newly diagnosed, early-stage breast cancer were collected from the Taiwan Cancer Registry database for 2003-2004. DM status and other comorbidities were retrieved from Taiwan's National Health Insurance database. The BCS and OS times of patients according to DM status were estimated via the Kaplan-Meier method. Cox's proportional hazard model was used to estimate adjusted hazard ratios (HRs) for the effects of DM, comorbidities, and other risk factors on mortality.

RESULTS

In total, 4,390 patients were identified and 341 (7.7%) presented with DM. The 5-year BCS and OS rates were significantly greater in DM patients than in non-DM patients (BCS, 85% versus 91%; OS, 79% versus 90%). Furthermore, after adjusting for clinicopathologic variables and comorbidities, DM remained an independent predictor of shorter BCS (adjusted HR, 1.53) and OS (adjusted HR, 1.71) times. Subgroup analyses also demonstrated a consistent prognostic influence of DM across different groups.

CONCLUSION

In Asian patients with early-stage breast cancer, DM is an independent predictor of lower BCS and OS rates, even after adjusting for other comorbidities. The integration of DM care as part of the continuum of care for early-stage breast cancer should be emphasized.

Death causes in breast cancer patients

BACKGROUND

Due to improved outcomes in breast cancer (BCa), the proportion of affected women dying of other causes has increased. Thus, a better survival of BCa requires knowledge of other causes of death.

MATERIALS AND METHODS

Data on the population, cancers, and causes of death were gathered from the nationwide Swedish Family-Cancer Database, enrolling ∼3.68 million Swedish women. A Cox regression model, comparing BCa patients against all other women, was applied. Cause-of-death-specific hazard ratios (HRs) were calculated for both underlying and multiple causes of death.

RESULTS

Among 641 000 deaths from 1987 to 2006, 48,000 were BCa patients. For underlying causes except BCa, the highest cause-specific HRs were found for diseases of pulmonary circulation {1.51 [95% confidence interval (CI) 1.36-1.68]}, suicide [1.39 (1.19-1.63)], and heart failure [1.29 (1.22-1.37)]. For specific multiple causes, the highest ratios were found for external causes [1.86 (1.80-1.91)] and gastrointestinal disease [1.68 (1.62-1.74)].

CONCLUSIONS

Diagnosis of BCa is associated with increased risks of dying of various causes, including external causes, heart failure, diseases of pulmonary circulation, and gastrointestinal disease. The study fulfills the gap in knowledge of death causes in BCa patients and suggests to draw more attention to comorbidities.

Lifestyle interventions for cardiovascular risk reduction in women with breast cancer

PURPOSE

The purpose of this paper is to identify risk factors for cardiovascular disease in women with breast cancer and review healthy lifestyle behaviors as essential risk reduction strategies.

FINDINGS

Women with breast cancer account for 22% of the 12 million cancer survivors. Women diagnosed with breast cancer often present with modifiable and non-modifiable cardiovascular risk factors and/or pre-existing co-morbid illness. Any one or a combination of these factors may increase the risk of cardiovascular disease. There is strong evidence that healthy eating and routine physical activity can reduce cardiovascular disease. Exercise improves cardiovascular fitness, body composition and quality of life in breast cancer survivors and observational studies suggest a survival benefit.

CLINICAL IMPLICATIONS

Lifestyle interventions including a healthy diet, regular physical activity, weight management and smoking cessation should be integrated into a survivorship care plan to reduce cardiovascular disease risk and promote better health for women with breast cancer.

Inhibiting PI3K reduces mammary tumor growth and induces hyperglycemia in a mouse model of insulin resistance and hyperinsulinemia

Women with type 2 diabetes (T2DM) are at greater risk of developing and dying from breast cancer than women without T2DM. Insulin resistance and hyperinsulinemia underlie the pathogenesis of T2DM. In the MKR mouse model of insulin resistance, we have previously shown increased activation of the phosphatidylinositol 3-kinase (PI3K)/Akt/mTOR pathway in association with accelerated mammary tumor growth. In this study, we demonstrate that inhibiting PI3K with the oral pan-class I PI3K inhibitor, NVP-BKM120 reduced the growth of Met-1 and MCNeuA mammary tumor orthografts in the MKR mouse. NVP-BKM120 treatment decreased phosphorylation of Akt and S6 ribosomal protein (S6rp); no change in Erk1/2 phosphorylation was seen. Hyperglycemia, hypertriglyceridemia and greater hyperinsulinemia developed in the MKR mice treated with NVP-BKM120. We previously reported reduced tumor growth using intraperitoneal rapamycin in the MKR mouse, with the development of hyperglycemia and hypertriglyceridemia. Therefore, we examined whether the oral PI3K/mTOR inhibitor NVP-BEZ235 augmented the tumor suppressing effects of PI3K inhibition. We also investigated the effect of targeted PI3K/mTOR inhibition on PI3K/Akt/mTOR and Erk1/2 signaling, and the potential effects on glycemia. NVP-BEZ235 suppressed the growth of Met-1 and MCNeuA tumor orthografts, and decreased Akt and S6rp phosphorylation, despite increased Erk1/2 phosphorylation in Met-1 orthografts of MKR mice. Less marked hyperglycemia and hyperinsulinemia developed with NVP-BEZ235 than NVP-BKM120. Overall, the results of this study demonstrated that inhibiting PI3K/Akt/mTOR signaling with the oral agents NVP-BKM120 and NVP-BEZ235 decreased mammary tumor growth in the hyperinsulinemic MKR mouse. Inhibiting PI3K alone led to more severe metabolic derangement than inhibiting both PI3K and mTOR. Therefore, PI3K may be an important target for the treatment of breast cancer in women with insulin resistance. Monitoring for hyperglycemia and dyslipidemia should be considered when using these agents in humans, given the metabolic changes detected in this study.

Obesity and breast cancer survival in ethnically diverse postmenopausal women: the Multiethnic Cohort Study

Breast cancer survival has been found to be lower in obese women, but few studies have evaluated ethnic variations in this association. This study examined all-cause and breast cancer-specific survival by body mass index (BMI) in the Multiethnic Cohort (MEC) study for African American, Native Hawaiian, Japanese American, Latino, and Caucasian women. Female MEC participants free of breast cancer, aged ≥50 years at cohort entry, and diagnosed with primary invasive breast cancer during follow-up were included in the analyses (n = 3,842). Cox proportional hazards regression was used to estimate the effect of pre-diagnostic adult BMI (<22.5, 22.5-24.9, 25.0-29.9, ≥30 kg/m(2)) on the risk of mortality. Mean age at diagnosis was 68.8 years (range 50-89 years). During a mean follow-up of 6.2 ± 3.8 years after diagnosis, there were 804 deaths that included 376 breast cancer-specific deaths. After adjustment for breast cancer characteristics, including hormone receptor status, stage at diagnosis, and treatment, obese women had a higher risk of all-cause [hazard ratio (HR) = 1.54; 95% confidence interval (CI): 1.23, 1.91] and breast cancer-specific (HR = 1.45; 95% CI: 1.05, 2.00) mortality compared to women with high-normal BMI; however, being overweight did not affect survival. There was no evidence of ethnic differences in the BMI effect on all-cause (P (interaction) = 0.87) or breast cancer-specific (P (interaction) = 0.63) mortality. Our findings are consistent with the literature that maintaining moderate weight throughout adult life may be beneficial for breast cancer survival in women and this appears to hold for all ethnic groups.

Dietary fiber, carbohydrates, glycemic index, and glycemic load in relation to breast cancer prognosis in the HEAL cohort

BACKGROUND

Dietary intake of fiber, carbohydrate, glycemic index (GI), and glycemic load (GL) may influence breast cancer survival, but consistent and convincing evidence is lacking.

METHODS

We investigated associations of dietary fiber, carbohydrates, GI, and GL with breast cancer prognosis among n = 688 stage 0 to IIIA breast cancer survivors in the Health, Eating, Activity, and Lifestyle (HEAL) study. Premenopausal and postmenopausal women from Western Washington State, Los Angeles County, and New Mexico participated. Usual diet was assessed with a food frequency questionnaire. Total mortality, breast cancer mortality, nonfatal recurrence, and second occurrence data were obtained from SEER (Surveillance, Epidemiology, and End Results) registries and medical records. Cox proportional hazards regression estimated multivariate-adjusted hazard ratios and 95% confidence intervals (CI).

RESULTS

During a median of 6.7 years follow-up after diagnosis, n = 106 total deaths, n = 83 breast cancer-specific deaths, and n = 82 nonfatal recurrences were confirmed. We observed an inverse association between fiber intake and mortality. Multivariate-adjusted hazard rate ratios (HRR) comparing high to low intake were 0.53 (95% CI 0.23-1.23) and 0.75 (95% CI 0.43-1.31). A threshold effect was observed whereby no additional benefit was observed for intakes of 9 g/d or more. Fiber intake was suggestively inversely associated with breast cancer-specific mortality (HRR = 0.68, 95% CI 0.27-1.70) and risk of nonfatal recurrence or second occurrence (HRR = 0.68, 95% CI 0.27-1.70), but results were not statistically significant.

CONCLUSION

Dietary fiber was associated with a nonsignificant inverse association with breast cancer events and total mortality. Further studies to assess and confirm this relationship are needed in order to offer effective dietary strategies for breast cancer patients.

IMPACT

Increasing dietary fiber may an effective lifestyle modification strategy for breast cancer survivors.

The impact of diabetes on survival in women with ovarian cancer

OBJECTIVE

Diabetes is increasingly common among cancer patients and plausible biologic mechanisms exist by which diabetes may influence cancer prognosis. We aimed to investigate the impact of diabetes on ovarian cancer outcomes.

METHODS

We assessed the outcomes of 570 non-diabetic and 72 diabetic patients with epithelial ovarian, fallopian tube, and primary peritoneal cancer over a ten-year period. All inpatient and outpatient records were reviewed. The primary end points were overall and disease-free survival.

RESULTS

Of the 642 cases, 11.2% had type II diabetes. Diabetics were more likely to be older, had a higher BMI (33.4 vs. 27.8), and had more comorbid conditions. Diabetics were less likely to have been surgically staged as compared to non-diabetics (p=0.04) although stage, grade, and likelihood of optimal cytoreduction were similar between groups. Over a period of 10 years, with an average of 44 months of follow-up, the median overall survival for diabetics was 1503 days. The median overall survival for non-diabetics was 2464 days (log rank test, p=0.02). In a Cox proportional hazards multivariable model, diabetes remained a significant predictor of overall survival (HR=2.04, p<0.01).

CONCLUSIONS

Diabetics with ovarian cancer demonstrate strikingly poorer survival. The underlying reason for this is yet unknown and deserves further attention. Differences in care, competing risks of death, and changes within the tumor biology are plausible mechanisms for the observed difference in survival.

Construction of a database for the evaluation and the clinical management of patients with breast cancer treated with antiestrogens and/or aromatase inhibitors

Breast cancer, mostly exhibiting an hormone-dependent pathogenesis, is a commonly diagnosed cancer in females.It is well known that sex steroids favor the process of carcinogenesis of breast tissue and anti-hormonal therapy of breast cancer aims to decrease the action of estrogens on this tissue. For this purpose, two different compounds are prevalently used: the Selective Estrogen Receptor Modulators, preventing the cancer cell to interact with estrogens, and Aromatase Inhibitors, inhibiting the tissue conversion of androgens into estrogens. Unfortunately, latter treatments negatively impact on bone mass leading to the onset of osteoporosis. For this purpose, we propose to build a database to afford, to store and analyze information about the effects of treatment with Selective Estrogen Receptor Modulators and/or Aromatase Inhibitors on bone metabolism in patients with breast cancer referred to Our Center. We will focus on the possibility of intervening to reduce the negative effects on bone both by the identification of modifiable risk factors and administration of specific therapies, in order to create a therapeutic, diagnostic standard workup for these diseases.

Clinically defined type 2 diabetes mellitus and prognosis in early-stage breast cancer

PURPOSE

Self-reported diabetes has been associated with poor breast cancer outcomes. Research is needed to investigate the relationship between biologically determined glycemic control and breast cancer prognosis.

METHODS

Archived baseline blood samples from the Women's Healthy Eating and Living Study were used to measure hemoglobin A1C (HbA1C) among 3,003 survivors of early-stage breast cancer (age of diagnosis, 28 to 70 years) observed for a median of 7.3 years for additional breast cancer events and 10.3 years for all-cause mortality. HbA1C levels provide an accurate, precise measure of chronic glycemic levels. Cox regression analysis was performed to assess whether baseline HbA1C levels predicted disease-free and overall survival.

RESULTS

Only 5.8% of women had chronic hyperglycemia (defined as HbA1C levels ≥ 6.5%). Those with HbA1C ≥ 6.5% were older and more likely to be less educated, have nonwhite ethnicity, be obese, and have more advanced breast cancer at diagnosis. HbA1C was significantly associated with overall survival (P(trend) < .001). After adjusting for confounders, risk of all-cause mortality was twice as high in women with HbA1C ≥ 7.0% compared with women with HbA1C less than 6.5% (hazard ratio [HR], 2.35; 95% CI, 1.56 to 3.54). For disease-free survival, there was a nonsignificant 30% increase in risk for HbA1C levels ≥ 7.0% (HR, 1.26; 95% CI, 0.78 to 2.02). During study follow-up, previously diagnosed rather than undiagnosed diabetes seemed to account for the increased risk.

CONCLUSION

Chronic hyperglycemia is statistically significantly associated with reduced overall survival in survivors of early-stage breast cancer. Further study of diabetes and its relationship to breast cancer outcomes is warranted.

Diabetes and prognosis in a breast cancer cohort

PURPOSE

Epidemiological studies indicated that type 2 diabetes mellitus may increase breast cancer risk and mortality. The aim of this retrospective cohort study was to examine the effect of diabetes on the clinical course and the prognosis of early stage breast cancer in relation to tumour and patient characteristics.

METHODS

The cohort analyzed in this study consisted of 4,056 patients with invasive primary breast cancer. We compared overall survival, distant metastasis-free survival and local recurrence free survival between breast cancer patients with and without diabetes.

RESULTS

In our cohort 276 breast cancer patients (6.8%) were affected by diabetes compared to 3,780 patients (93.2%) without diabetes. Women with diabetes were significantly older, had larger tumours, and a higher rate of lymph node involvement. After a follow-up period of 5 years, stratification for age and adjustment for other prognostic factors, overall mortality following breast cancer was significantly higher in diabetic breast cancer patients (hazard ratio, HR 1.92; 95% confidence interval, CI 1.49-2.48). We found no significant differences in distant metastasis-free survival and local recurrence free survival between the two groups, but we found a slightly significant higher rate of distant metastasis in the group of patients with diabetes and oestrogen receptor negative tumours (HR 2.28; CI 1.31-3.97).

CONCLUSION

In this study, patients with diabetes and oestrogen receptor negative breast cancer had a more than 2-fold higher risk for distant metastasis compared to patients without diabetes. Diabetes was also associated with an almost 2-fold increase in mortality within the 5 years follow-up period.

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.